A Remark on the Method of Electron Beam Energy Measurement Using Laser Light Resonance Abso
a r X i v :h e p -p h /0503004v 1 1 M a r 2005A REMARK ON THE METHOD OF ELECTRON BEAM ENERGY MEASUREMENT USING LASER LIGHT RESONANCE ABSORPTION.N.B.Skachkov,Joint Institute for Nuclear Research,Dubna,141980,Russia E-mail:skachkov@jinr.ru,skachkov@https://www.wendangku.net/doc/7211070788.html, February 2,2008Abstract The problem of measuring of the electron beam energy by help of the laser light interaction with the electrons is discussed.It is shown that the orthogonal orien-tation of the laser beam with respect to the electron one,proposed in the present Note,may allow to perform this measurement in accordance with the physical na-ture of a formation of an electron quantum levels in a magnetic ?eld.In result,the ?nal formula,that expresses the beam energy through the strength of a magnetic ?eld and the energy of the laser photon,gets a transparent physical meaning and do contain a less number of parameters (what may lead to an increase of the precision of the measurement).Some other sequences from this proposal,like the change of the geometry of the experimental set-up and the necessity of a new additional
detector to register the products of the Compton scattering for monitoring of the beam energy measurements,are discussed also.
1Introduction.
An application of the resonance absorption (RA)of the light by electron [1]-[6]for the beam energy measurements was discussed in a number of talks given at di?erent conferences [5],[6].
The idea of this method is based on the theoretical formula which was obtained for the ?rst time in the framework of the non-relativistic quantum mechanics (see [7])and latter on was generalized for the relativistic case basing upon the Dirac and the Klien-Gordon equations (see,for instance [8]).These formulae give the energy eigenvalues and the wave functions of the particle which moves in the homogeneous magnetic ?eld.The analogous exact solutions were found also for a more complicated cases when a particle moves in
1
the combined?eld,composed of an electromagnetic and a homogeneous magnetic?elds (Volkov solution,see also[9],[10]).Recently this study was continued by?nding out the exact solution of the Dirac equation for a case of the superposition of a homogeneous magnetic?eld and a circularly polarized electromagnetic wave[4]with an account of the electron anomalous magnetic moment.Its was shown that taking account of the electron anomalous magnetic moment removes the spin degeneracy of the energy levels.
According to the results of all these papers the particle which moves in a constant homogeneous magnetic?eld should have the quantized values of the energy,connected with its motion in the plane perpendicular to its velocity vector.In[1]and latter on in[4]it was proposed to use the transition from the lower levels of quantized transverse energy to the higher ones,caused by the laser photons absorption,for getting out the information about the initial electron beam energy(let us mention that in these papers the process of laser photon interaction with the beam electron was described within the Classical Electrodynamics framework).
In the present Note some new points of views on this measurement are proposed. First,the suggestion of a new orthogonal disposition of the laser beam with respect to the electron one is presented.Such a geometry of the measurement is di?erent to the previously considered case,see[1]and[6],where the laser beam was supposed to be injected at a small angle to the electron beam direction(taken as z-axis).New proposal is based on the arguments which follow from the physical origin of the quantized levels of the electron energy in a magnetic?eld and would be discussed below in Section2.The second point is connected with the usage of Quantum Electrodynamics(QED)approach for describing the laser photon interaction with the beam electron(see Section3).The importance of the measurement of the Compton scattering(as the process that may happen when the experimental parameters would not meet the conditions necessary for RA)for monitoring of the beam energy measurement is discussed in the Sections4and 5.
2The energy levels and the wave function of the elec-tron in the static magnetic?eld.
Here(having in mind the aim of a further application for the beam energy measurements at ILC,1i.e.at the ultra-relativistic energies of electron)the solution of the Dirac equation would be used(taken from the widely used text book[11]),derived for a case of the electron motion in the homogeneous magnetic?eld( B=rot A),and with the choice of the Landau gauge for the4-vector of the electromagnetic potential Aμ:A0=A x= A z=0,A y=B0x.Thus, A=B0x e y,where e y is the unit vector along the y-axis,and B=(0,0,B
).
z
The energy of the electron p0,which is the fourth component of the electron4-momentum vector Pμ=(p0,p x,p y,p z),is de?ned in this case by formula([11]):
(p0)2≡E2λ(n,p z)=E2z+E2T,λ(n),(1) where the?rst term
E2z=m2e c4+p2z c2(2) is the square of the relativistic energy of a free electron that moves in a beam(taken as the z-axis).The second term
E2T,λ(n)=h(
eB0
m e =ωc is the cyclotron frequency.
In what follows we shall use the expression for the di?erence of E2T,λ(n)for the two neighboring values of energy levels with n+1and n quantum numbers which stems from the formula(3):
?E2T,λ=E2T,λ(n+1)?E2T,λ(n)=2h(
eB0
2the ground state(i.e.,
n=0)would have,as it follows from(3),the value of the transversal energy been equal to zero:2
E2
T,λ=?1
2the expression for the total
energy of the electron in magnetic?eld do coincides with the energy of a free electron:
Eλ=?1m2e c4+p2z c2.(6) In a complete correspondence with the formula(1),that demonstrates the independent entrance of E2z and E2T terms into the expression of the square of the total energy E2n,λ,3 the wave functions of the Dirac equation,found as the exact solutions for the mentioned above di?erent combinations of external magnetic and electric?elds[1]-[11],also do factorize in two parts.
One part(an oscillator like solution)describes the motion in the plane transverse to the beam and along the x-axis(because the only nonzero component A y=B0x of the
2,would have the energy
E2
T,λ=+1
4-vector of the electromagnetic potential Aμis de?ned by the x-coordinate).The another one,which has an exponential form,is connected with the free motions along the y-and z-axis(see[7]-[11]).For example,the solution,that corresponds to the formula(1),has a form( r=(x,y,z))[11]:
ψ( r)=e i(p y y+p z z)f(x),(7) where
f(x)=Ce?ξ2/2H n(ξ);ξ=
(with the4-momentum p1)looks,in a general case,like(k2and p2are the?nal state momenta of the photon and the electron):
p1+k1=p2+k2.(9) If we shall pass to the components of the4-momentum:kμ=(k0, k); k=( k T,k z),then the equation(9)may be presented as a set of the independent conservation laws for each component separately:
for the energy,
p01+k01=p02+k02,(10) for the z-projection:
p z1+k z1=p z2+k z2,(11) and for the transversal one
p T
+ k T1= p T2+ k T2.(12)
1
Thus,if the laser photon would have some small angleθto the electron beam,as it was considered in[1]and[6](in such a case the k z1component of the photon momentum would dominate over his transverse one k T1),then the z-component of the electron would change,in general case,from p z1to some p z2due to the conservation law of the z-component of4-momentum.
Independently from the z-component,the transversal component of electron may also change after the interaction.There are two possible cases,which may be realized in the framework of QED.
The?rst one,most simple,may be realized when the k T1contribution to the electron transversal motion would not match the di?erence(4)of two quantized electron energy levels in a magnetic?eld.In this case,according to QED a pure Compton scattering would take a place.
The second one may happen when the value of| k T1|should match the equation(4).In this case,keeping in mind what was written before about the independent conservation of z-and transverse components of the total4-momentum of electron-photon system,we shall have the?nal state consisting of:
.the photon,radiated due to changing of the electron momentum z-component(and in accordance with(11)),
.and the electron,which| p T2|should be de?ned in this case by formula(3)for the (n+1)-th,or even higher level,if it was at the n-th orbit in the initial state.
Hence,in both cases,even if the resonance condition would be ful?lled and the trans-verse component k T1would exactly coincide with the energy necessary for moving from the lower orbit to the higher one(i.e.the equality p T2= p T1+ k T1would be ful?lled for the inde-pendent(!)motion in the transverse plane),the changing of the independent z-component
5
of the electron momentum would lead to the radiation from the electron.In QED it is an emission of the photon via the e2order Compton process.4
In other words,according to QED,in a case,when the laser beam would have a small angleθwith respect to the electron beam,the Compton process(with or without moving of an electron from the lower orbit to a higher one)would take place and the emission of the photon would happen.In such a case the whole situation becomes more complicated for the theoretical description.5
A possible simple way to avoid these problems and to use the theoretical prediction about the existence of the quantized energy levels(of the transverse motion of the particle in the magnetic?eld)for the electron beam measurement is given below.It is based on a special choice of the angle between the laser and the electron beams,mentioned already in the Introduction.
4What laser photon beam orientation meets better the physics of electron motion in magnetic?eld? The physical picture of the electron motion in the static magnetic?eld as been a sum of two independent motions(what was discussed in the previous Sections)as well as the 4-momentum conservation equations written above,do prompt(if not to say,dictate)an easy way to prepare the initial state to use the possibilities connected with existing of the quantized energy levels of a particle in the magnetic?eld.This possibility is based on the proper choice of the relative geometrical orientation of the laser and the electron beams.
Indeed,if we shall choose the laser beam to be orthogonal to the electron one,i.e. shall consider a case when k z1=0in equation(11),then the collision of the laser photon with the electron would not e?ect the z-component of the electron momentum at all.
If also,in addition to the orthogonal angle orientation,we shall adjust the laser photons energy(and the magnetic?eld strength B0)6to be equal to the di?erence of the two lowest quantized levels of energy,connected with the transversal motion of the electron in a magnetic?eld and de?ned by formula(4),then the laser photon would be absorbed.7In this case the whole initial photon energy,been prepared as of the transversal nature only, would transform into the energy of a its circular motion,but on a higher then previous one orbit in the plane transverse to electron beam.Therefore,in a case of the proposed
orthogonal orientation and the properly tuned value of the magnetic?eld strength B0in a way to have the di?erence of two energy levels of the electron in accordance with the energy of the laser photons there would be no any phase space left for the production of an additional photon in the?nal state!
In this special case of k z1=0and when also the laser energy would?t the di?erence of two E T for some n and n+1levels,the formula(11)shall take a very simple form:
p z1=p z2.(13) (This equation may be treated also as one of the conditions of RA e?ect.) The energy conservation law in the such a case ofθlaser=900should look like
p01+k01=p02,(14) where,due to our choice of the laser photon momentum4-vector in a form kμ1=(k01, k1); k
=( k1T,0),the?nal state electron transverse momentum p T2would be de?ned by the 1
the equation
p T
+ k T1= p T2,(15)
1
as the sum of the initial electron transverse momentum p T1and the laser photon transverse vector k T1which modulus is equal to the energy of the absorbed photon8.
The4-component equation(9)would take in such a case the following form:
p1+k1=p2.(16) Note that for the considered here process the right hand side of equation(14)may be represented like
p02=
8i.e.,k0
=| k1T|due to the relation k01=| k1|,which is valid for the massless photon.
1
7
2Eγlas Eλ(n,p z1)+(Eγlas)2=E2λ(n+1,p z1)?E2λ(n,p z1).(20) From formula(1)-(3)it is clear that the longitudinal contributions E2z would cancel in the right hand side of(20)9and only the di?erence of the transverse energies E2T,λ(n)would remain there:
E2λ(n+1,p z1)?E2λ(n,p z1)=E2T,λ(n+1)?E2T,λ(n).(21) The expression for this di?erence was already given by formula(4).So formula(20) could be presented in a form
2Eγlas Eλ(n,p z1)+(Eγlas)2=?E2T,λ,(22)
which does not contain any more the dependence on the beam energy in the right hand side of the equation.In such a case it is convenient to present(22)as an equation which includes the dependence on the electron beam energy(see(1))only in the left hand side:
Eλ(n,p z1)=
?E2T,λ?(Eγlas)2
2
),then the formula(23)(written as Eλ=?1m2e c4+p2z c2=E beam)gives,due to (6),the following expression for the beam energy E beam
E beam=?E2
T,λ=?1
2Eγlas
.(24)
Keeping in mind that according to formula(4)for the non spin-?ip case,i.e.when the value ofλdoes not change in the process of the beam electron interaction with the the laser photon,we have?E2T,λ=2hωc(m e c2)=2h(eB0/m e)(m e c2),we come to a very simple?nal formula
E beam=2h(eB0
2Eγlas
.(25)
The last equation does express the value of the beam energy through those values of the magnetic?eld strength B0and of the laser photon energy Eγlas,which were tuned to provide the conditions for the laser photon energy to be equal to the di?erence of two neighboring quantum energy levels in a case of the orthogonal relative orientation of the laser to the electron beams.
It is natural that the error of the measurement of the electron beam energy?E beam should be de?ned in this case by two errors only:
.the error of the magnetic?eld strength?B0measurement,and by
.the error of the measurement of the laser photon energy?Eγlas.
To summarize shortly it is possible to say that in a case when the following conditions would be ful?lled:
*the angle between the laser and the electron beams would be chosen to beθ=900, (i.e.cosθ=0),
**the magnetic?eld strength B0and the laser photon energy Eγlas would be tuned to provide the conditions for the laser energy to be equal to the di?erence of two neighboring quantum energy levels of the electron in a homogeneous magnetic?eld,
then the photon may be absorbed by the quantum system of the quantized electron levels in a homogeneous magnetic?eld and
the laser photon collision with the beam electron may lead only to a change of the orbit number of the transverse motion of the electron.No changes of the longitudinal(i.e.,of z-)component of the electron momentum would happen.It means that no any additional radiation(like that one which take place in the Compton scattering process)would have su?cient phase space to appear.
5How it may look from the experimentalist point of view.
There are some points have to be discussed in a connection with a possible planning of the measurements if they should be done in the context of the described above picture of the laser photon interaction with the beam electron.
The obvious question needed to be asked for such a planning would be about the choice of the laser energy(i.e.,the wave length).The answer can be easily found from the solution of the quadratic equation(25)for the Eγlas.In a case of n=0andλ=?1
1+2h(eB0
E2beam
?1)=E beam(
E2beam?1),(26)
which expresses Eγlas through the value of the beam energy E beam and the strength of the
magnetic?eld B0.So,with the help of this formula one can?nd out(for a chosen value of E beam and an expected value of B0)what kind of a laser does have the wave length that corresponds to the energy de?ned by formula(27).
The next important sequence for planning of the experiment is the need to pass to a new geometry for the experimental set-up for such measuring of dropping of the laser light intensity due to the photon absorption.It is evident that the detector(D),proposed to measure the decrease of the laser light intensity after its interaction with the electron beam[6],and the laser should be placed on the same line,perpendicular to the electron beam.Such a geometrical disposition of the experimental setup looks very di?erent to what was discussed in[1]-[6],where it was proposed that the line which connects the laser and the detector(D)would have a small angleθto the electron beam line.
This changing of the position of the detector D may be important from the experimen-tal point of view.Really,in principle,there is a non zero probability that the electron, which was forced by the laser light to move to a higher orbit,would emit a photon and then return after some time back onto the ground state orbit.Here we have a direct analogy with the radiative transition from higher to lower orbits in atoms.Fortunately, in the case,proposed in the present Note,the electron,been moved onto any the higher orbit,would keep,as it was discussed in the previous Sections,the same value of the initial longitudinal momentum p z1(as it was discussed in the previous Sections),i.e.,it shall con-tinue to move with the same speed,practically equal to the speed of light.Hence,if the photon emission would happen at some moment,de?ned by the lifetime of the“n+1-th”excitation level,nevertheless,this photon have no chances to hit the detector D,because during this even small time the electron,that was pushed to the“n+1-th”orbit,would ?y already away from the position of the“laser-detector D”perpendicular line(to the electron beam line).To this reason the proposed here perpendicular orientation of the laser to electron beam is a preferable one as it is more safe from the view point of the possibility that the secondary radiative photon emission may reach the detector D.
Up to now we were discussing the aspects connected with the case of the resonance absorption within the situation of a new orthogonal disposition of both beams.Now let us turn to the situation when the energy of the laser photon would not?t to the the value of energy splitting between the main n=0and one of the next to the ground states levels.
As it was already discussed in the previous Sections,in a case when the resonance condition(25)would not be ful?lled(most probably,due to some variation of the electron beam energy)then according to QED the Compton process ofγ+e→γ+e scattering would take place.
The appearance of the Compton scattering products,i.e.of the?nal state photon and electron(with p z2=p z1)may be used as the signal of a dropout from the resonance condition(25).Therefore,the addition of experimental equipment,supposed for beam energy measurement,by a new detector which may identify the electrons and photons, produced in the Compton scattering,may be very helpful.It may be an electromagnetic calorimeter with the appropriate granulation for the registration of the photons and for de?ning of their position,accompanied by some electron tracker.11
It should be mentioned also that if we shall suppose that the e?ects of the electron beam energy variation would not be so large,then it would not be so di?cult to calculate the angle and energy distributions of the scattered photons and electrons which would be characteristic for the such possible variations of the electron beam energy in both directions from the position of the resonance value.
Thus,it may happen so that the control over the Compton process(by a comparison of the observed experimental distributions of the photon and the electron parameters with those predicted by QED)would turn out to be a useful guide for adjusting the magnetic ?eld strength B0during the beam energy measurement.In such a case the measuring of the characteristics of the Compton scattering within the region of parameters,close to the resonance position,may be used for the on-line tuning of the magnetic?eld strength to those values which would be an adequate to keep the resonance condition.The detailed study of this possibility would be a subject of the following publications.
6Summary.
It is shown that the orthogonal orientation of the laser photon beam with respect to the electron beam allows to bring the idea of the use of the theoretical prediction about the existence of electron quantum levels(in the presence of the homogeneous magnetic?eld) in the correspondence with the physical origin of these resonance levels.
In result,the formulae that describe a process of a possible absorption of the laser light by the transverse degrees of electron motion in the constant magnetic?eld become much simpler because in this case the absorption process does not interfere with the longitudinal motion along the beam direction.Due to this no additional radiation would appear in a case when the laser photon energy would?t the value of the energy splitting of two electron levels in the magnetic?eld(i.e.in a case of ful?lling the resonance condition). In result,the physical picture of the process of measuring the electron beam energy by measuring the drop of the laser light intensity in the absorption process becomes more transparent.This new relative orientation of two beams means also passing to another geometry for experimental tools set-up.
In the opposite case when the energy of the laser photon would not be equal to the di?erence of two electron energy levels(in magnetic?eld)the Compton scattering process would take place.The characteristics of the scattered electron and photon(angles and energies)may be measured(it may require to enlarge the experimental equipment by the additional electromagnetic calorimeter and the tracker)and then used for an on-line monitoring of the process of tuning the magnetic?eld to keep the resonance photon absorption condition(25)for the electron beam energy measurement.
It is a pleasure for the author to express his gratitude to R.Melikian and especially to H.J.Schreiber for the useful discussions.
References
[1]I.A.Gilinski and K.A.Ryasantsev;Izv.Vuz.Radiophysics,5(1964)838;
[2]V.G.Bagrov and V.R.Khalilov;Izv.Vuz.Physics,2(1968)37;
[3]https://www.wendangku.net/doc/7211070788.html,ant’ev;https://www.wendangku.net/doc/7211070788.html,pekhi,40,1(1971)1;Uspekhi Fiz.Nauk,167,1(1997)37;
[4]R.A.Melikian and D.P.Barber,DESY report98-015(1998),hep-ph/9903007;
[5]R.A.Melikian and D.P.Barber Proc.13Intern.Symposium on High Energy Spin
Physics(Spin98),p.495,Protvino,Russia,8-12Sept.1998;
[6]D.P.Barber and R.A..Melikian,Procc.of EPAC2000,Vienna,Austria,p.996,
http://accelconf.web.cern.ch/accelconf/e00/PAPERS/MOP1B01.pdf;
[7]https://www.wendangku.net/doc/7211070788.html,ndau and E.M.Lifshitz,”Quantum Mechanics”,Nauka,Moscow,1989.
[8]A.A.Sokolov,I.M.Ternov and C.W.Kilminster”Radiation from Relativistic Elec-
trons”,American Institute of Physics(translation series),1986;Naika,Moscow,1983.
[9]P.J.Redmond,J.Math.Phys.6(1965)1163;
[10]J.Bergou,F.Ehlotzky,Phys.Rev A27(1983)2291;
[11]A.I.Akhiezer,V.B.Berestetskii”Quantum Electrodynamics,Fizmatgiz,Moscow,
1957.Interscience Publishes,New York,1965;
[12]V.B.Berestetskii,E.M.Lifshitz,L.P.Pitaevskii,”Quantum Electrodynamics”,Nauka,
Moscow,1980;Pergamon press(1982),Addison Wesley Publ.,1971;
[13]N.N.Bogoluibov,D.V.Shirkov“Introduction to the Theory of Quantized Fields”,Fiz-
matgiz,Moscow,1957;A Wiley-Interscience Publication;John Wiley and Sons,New York,1979;
[14]TESLA.Technical Design Report http://tesla.desy.de/tdr/Chapter IV,The Photon
Collider at TESLA http://tesla.desy.de/tdr/PartVI/append.html.
12
on the contrary的解析
On the contrary Onthecontrary, I have not yet begun. 正好相反，我还没有开始。 https://www.wendangku.net/doc/7211070788.html, Onthecontrary, the instructions have been damaged. 反之，则说明已经损坏。 https://www.wendangku.net/doc/7211070788.html, Onthecontrary, I understand all too well. 恰恰相反，我很清楚 https://www.wendangku.net/doc/7211070788.html, Onthecontrary, I think this is good. ⑴我反而觉得这是好事。 https://www.wendangku.net/doc/7211070788.html, Onthecontrary, I have tons of things to do 正相反，我有一大堆事要做 Provided by jukuu Is likely onthecontrary I in works for you 反倒像是我在为你们工作 https://www.wendangku.net/doc/7211070788.html, Onthecontrary, or to buy the first good. 反之还是先买的好。 https://www.wendangku.net/doc/7211070788.html, Onthecontrary, it is typically american. 相反，这正是典型的美国风格。 222.35.143.196 Onthecontrary, very exciting.
恰恰相反，非常刺激。 https://www.wendangku.net/doc/7211070788.html, But onthecontrary, lazy. 却恰恰相反，懒洋洋的。 https://www.wendangku.net/doc/7211070788.html, Onthecontrary, I hate it! 恰恰相反，我不喜欢！ https://www.wendangku.net/doc/7211070788.html, Onthecontrary, the club gathers every month. 相反，俱乐部每个月都聚会。 https://www.wendangku.net/doc/7211070788.html, Onthecontrary, I'm going to work harder. 我反而将更努力工作。 https://www.wendangku.net/doc/7211070788.html, Onthecontrary, his demeanor is easy and nonchalant. 相反，他的举止轻松而无动于衷。 https://www.wendangku.net/doc/7211070788.html, Too much nutrition onthecontrary can not be absorbed through skin. 太过营养了反而皮肤吸收不了. https://www.wendangku.net/doc/7211070788.html, Onthecontrary, I would wish for it no other way. 正相反，我正希望这样 Provided by jukuu Onthecontrary most likely pathological. 反之很有可能是病理性的。 https://www.wendangku.net/doc/7211070788.html, Onthecontrary, it will appear clumsy. 反之，就会显得粗笨。 https://www.wendangku.net/doc/7211070788.html,
英语造句
一般过去式 时间状语：yesterday just now (刚刚) the day before three days ag0 a week ago in 1880 last month last year 1. I was in the classroom yesterday. I was not in the classroom yesterday. Were you in the classroom yesterday. 2. They went to see the film the day before. Did they go to see the film the day before. They did go to see the film the day before. 3. The man beat his wife yesterday. The man didn’t beat his wife yesterday. 4. I was a high student three years ago. 5. She became a teacher in 2009. 6. They began to study english a week ago 7. My mother brought a book from Canada last year. 8.My parents build a house to me four years ago . 9.He was husband ago. She was a cooker last mouth. My father was in the Xinjiang half a year ago. 10.My grandfather was a famer six years ago. 11.He burned in 1991
学生造句--Unit 1
●I wonder if it’s because I have been at school for so long that I’ve grown so crazy about going home. ●It is because she wasn’t well that she fell far behind her classmates this semester. ●I can well remember that there was a time when I took it for granted that friends should do everything for me. ●In order to make a difference to society, they spent almost all of their spare time in raising money for the charity. ●It’s no pleasure eating at school any longer because the food is not so tasty as that at home. ●He happened to be hit by a new idea when he was walking along the riverbank. ●I wonder if I can cope with stressful situations in life independently. ●It is because I take things for granted that I make so many mistakes. ●The treasure is so rare that a growing number of people are looking for it. ●He picks on the weak mn in order that we may pay attention to him. ●It’s no pleasure being disturbed whena I settle down to my work. ●I can well remember that when I was a child, I always made mistakes on purpose for fun. ●It’s no pleasure accompany her hanging out on the street on such a rainy day. ●I can well remember that there was a time when I threw my whole self into study in order to live up to my parents’ expectation and enter my dream university. ●I can well remember that she stuck with me all the time and helped me regain my confidence during my tough time five years ago. ●It is because he makes it a priority to study that he always gets good grades. ●I wonder if we should abandon this idea because there is no point in doing so. ●I wonder if it was because I ate ice-cream that I had an upset student this morning. ●It is because she refused to die that she became incredibly successful. ●She is so considerate that many of us turn to her for comfort. ●I can well remember that once I underestimated the power of words and hurt my friend. ●He works extremely hard in order to live up to his expectations. ●I happened to see a butterfly settle on the beautiful flower. ●It’s no pleasure making fun of others. ●It was the first time in the new semester that I had burned the midnight oil to study. ●It’s no pleasure taking everything into account when you long to have the relaxing life. ●I wonder if it was because he abandoned himself to despair that he was killed in a car accident when he was driving. ●Jack is always picking on younger children in order to show off his power. ●It is because he always burns the midnight oil that he oversleeps sometimes. ●I happened to find some pictures to do with my grandfather when I was going through the drawer. ●It was because I didn’t dare look at the failure face to face that I failed again. ●I tell my friend that failure is not scary in order that she can rebound from failure. ●I throw my whole self to study in order to pass the final exam. ●It was the first time that I had made a speech in public and enjoyed the thunder of applause. ●Alice happened to be on the street when a UFO landed right in front of her. ●It was the first time that I had kept myself open and talked sincerely with my parents. ●It was a beautiful sunny day. The weather was so comfortable that I settled myself into the
英语句子结构和造句
高中英语~词性~句子成分~语法构成 第一章节：英语句子中的词性 1.名词：n. 名词是指事物的名称，在句子中主要作主语.宾语.表语.同位语。 2.形容词;adj. 形容词是指对名词进行修饰~限定~描述~的成份，主要作定语.表语.。形容词在汉语中是（的）.其标志是: ous. Al .ful .ive。. 3.动词：vt. 动词是指主语发出的一个动作，一般用来作谓语。 4.副词：adv. 副词是指表示动作发生的地点. 时间. 条件. 方式. 原因. 目的. 结果.伴随让步. 一般用来修饰动词. 形容词。副词在汉语中是（地）.其标志是：ly。 5.代词：pron. 代词是指用来代替名词的词，名词所能担任的作用，代词也同样.代词主要用来作主语. 宾语. 表语. 同位语。 6.介词：prep.介词是指表示动词和名次关系的词，例如：in on at of about with for to。其特征：
介词后的动词要用—ing形式。介词加代词时，代词要用宾格。例如：give up her（him）这种形式是正确的，而give up she（he）这种形式是错误的。 7.冠词：冠词是指修饰名词，表名词泛指或特指。冠词有a an the 。 8.叹词：叹词表示一种语气。例如：OH. Ya 等 9.连词：连词是指连接两个并列的成分，这两个并列的成分可以是两个词也可以是两个句子。例如：and but or so 。 10.数词：数词是指表示数量关系词，一般分为基数词和序数词 第二章节：英语句子成分 主语：动作的发出者，一般放在动词前或句首。由名词. 代词. 数词. 不定时. 动名词. 或从句充当。 谓语：指主语发出来的动作，只能由动词充当，一般紧跟在主语后面。 宾语：指动作的承受着，一般由代词. 名词. 数词. 不定时. 动名词. 或从句充当. 介词后面的成分也叫介词宾语。 定语：只对名词起限定修饰的成分，一般由形容
六级单词解析造句记忆MNO
M A: Has the case been closed yet? B: No, the magistrate still needs to decide the outcome. magistrate n.地方行政官，地方法官，治安官 A: I am unable to read the small print in the book. B: It seems you need to magnify it. magnify vt.１．放大，扩大；２．夸大，夸张 A: That was a terrible storm. B: Indeed, but it is too early to determine the magnitude of the damage. magnitude n.１．重要性，重大；２．巨大，广大 A: A young fair maiden like you shouldn’t be single. B: That is because I am a young fair independent maiden. maiden n.少女，年轻姑娘，未婚女子 a.首次的，初次的 A: You look majestic sitting on that high chair. B: Yes, I am pretending to be the king! majestic a.雄伟的，壮丽的，庄严的，高贵的 A: Please cook me dinner now. B: Yes, your majesty, I’m at your service. majesty n.１．［Ｍ－］陛下（对帝王，王后的尊称）；２．雄伟，壮丽，庄严 A: Doctor, I traveled to Africa and I think I caught malaria. B: Did you take any medicine as a precaution? malaria n.疟疾 A: I hate you! B: Why are you so full of malice? malice n.恶意，怨恨 A: I’m afraid that the test results have come back and your lump is malignant. B: That means it’s serious, doesn’t it, doctor? malignant a.１．恶性的，致命的；２．恶意的，恶毒的 A: I’m going shopping in the mall this afternoon, want to join me? B: No, thanks, I have plans already. mall n.（由许多商店组成的）购物中心 A: That child looks very unhealthy. B: Yes, he does not have enough to eat. He is suffering from malnutrition.
base on的例句
意见应以事实为根据. 3 来自辞典例句 192. The bombers swooped ( down ) onthe air base. 轰炸机 突袭 空军基地. 来自辞典例句 193. He mounted their engines on a rubber base. 他把他们的发动机装在一个橡胶垫座上. 14 来自辞典例句 194. The column stands on a narrow base. 柱子竖立在狭窄的地基上. 14 来自辞典例句 195. When one stretched it, it looked like grey flakes on the carvas base. 你要是把它摊直, 看上去就象好一些灰色的粉片落在帆布底子上. 18 来自辞典例句 196. Economic growth and human well - being depend on the natural resource base that supports all living systems. 经济增长和人类的福利依赖于支持所有生命系统的自然资源. 12 1 来自辞典例句 197. The base was just a smudge onthe untouched hundred - mile coast of Manila Bay. 那基地只是马尼拉湾一百英里长安然无恙的海岸线上一个硝烟滚滚的污点. 6 来自辞典例句 198. You can't base an operation on the presumption that miracles are going to happen. 你不能把行动计划建筑在可能出现奇迹的假想基础上.
英语造句大全
英语造句大全English sentence 在句子中，更好的记忆单词！ 1、(1)、able adj. 能 句子：We are able to live under the sea in the future. (2)、ability n. 能力 句子：Most school care for children of different abilities. (3)、enable v. 使。。。能句子：This pass enables me to travel half-price on trains. 2、(1)、accurate adj. 精确的句子：We must have the accurate calculation. (2)、accurately adv. 精确地 句子：His calculation is accurately. 3、(1)、act v. 扮演 句子：He act the interesting character. （2）、actor n. 演员 句子：He was a famous actor. (3)、actress n. 女演员 句子：She was a famous actress. (4)、active adj. 积极的 句子：He is an active boy. 4、add v. 加 句子：He adds a little sugar in the milk. 5、advantage n. 优势 句子：His advantage is fight. 6、age 年龄n. 句子：His age is 15. 7、amusing 娱人的adj. 句子：This story is amusing. 8、angry 生气的adj. 句子：He is angry. 9、America 美国n.
(完整版)主谓造句
主语+谓语 1. 理解主谓结构 1) The students arrived. The students arrived at the park. 2) They are listening. They are listening to the music. 3) The disaster happened. 2．体会状语的位置 1) Tom always works hard. 2) Sometimes I go to the park at weekends.. 3) The girl cries very often. 4) We seldom come here. The disaster happened to the poor family. 3. 多个状语的排列次序 1) He works. 2) He works hard. 3) He always works hard. 4) He always works hard in the company. 5) He always works hard in the company recently. 6) He always works hard in the company recently because he wants to get promoted. 4. 写作常用不及物动词 1. ache My head aches. I’m aching all over. 2. agree agree with sb. about sth. agree to do sth. 3. apologize to sb. for sth. 4. appear (at the meeting, on the screen) 5. arrive at / in 6. belong to 7. chat with sb. about sth. 8. come (to …) 9. cry 10. dance 11. depend on /upon 12. die 13. fall 14. go to … 15. graduate from 16. … happen 17. laugh 18. listen to... 19. live 20. rise 21. sit 22. smile 23. swim 24. stay (at home / in a hotel) 25. work 26. wait for 汉译英： 1.昨天我去了电影院。 2.我能用英语跟外国人自由交谈。 3.晚上7点我们到达了机场。 4.暑假就要到了。 5.现在很多老人独自居住。 6.老师同意了。 7.刚才发生了一场车祸。 8.课上我们应该认真听讲。9. 我们的态度很重要。 10. 能否成功取决于你的态度。 11. 能取得多大进步取决于你付出多少努力。 12. 这个木桶能盛多少水取决于最短的一块板子的长度。
初中英语造句
【it's time to和it's time for】 ——————这其实是一个句型,只不过后面要跟不同的东西. ——————It's time to跟的是不定式（to do）.也就是说,要跟一个动词,意思是“到做某事的时候了”.如： It's time to go home. It's time to tell him the truth. ——————It's time for 跟的是名词.也就是说,不能跟动词.如： It's time for lunch.(没必要说It's time to have lunch) It's time for class.(没必要说It's time to begin the class.) They can't wait to see you Please ask liming to study tonight. Please ask liming not to play computer games tonight. Don’t make/let me to smoke I can hear/see you dance at the stage You had better go to bed early. You had better not watch tv It’s better to go to bed early It’s best to run in the morning I am enjoy running with music. With 表伴随听音乐 I already finish studying You should keep working. You should keep on studying English Keep calm and carry on 保持冷静继续前行二战开始前英国皇家政府制造的海报名字 I have to go on studying I feel like I am flying I have to stop playing computer games and stop to go home now I forget/remember to finish my homework. I forget/remember cleaning the classroom We keep/percent/stop him from eating more chips I prefer orange to apple I prefer to walk rather than run I used to sing when I was young What’s wrong with you There have nothing to do with you I am so busy studying You are too young to na?ve I am so tired that I have to go to bed early
The Kite Runner-美句摘抄及造句
《The Kite Runner》追风筝的人--------------------------------美句摘抄 1.I can still see Hassan up on that tree, sunlight flickering through the leaves on his almost perfectly round face, a face like a Chinese doll chiseled from hardwood: his flat, broad nose and slanting, narrow eyes like bamboo leaves, eyes that looked, depending on the light, gold, green even sapphire 翻译：我依然能记得哈桑坐在树上的样子，阳光穿过叶子，照着他那浑圆的脸庞。他的脸很像木头刻成的中国娃娃，鼻子大而扁平，双眼眯斜如同竹叶，在不同光线下会显现出金色、绿色，甚至是宝石蓝。 E.g.: A shadow of disquiet flickering over his face. 2.Never told that the mirror, like shooting walnuts at the neighbor's dog, was always my idea. 翻译：从来不提镜子、用胡桃射狗其实都是我的鬼主意。E.g.:His secret died with him, for he never told anyone. 3.We would sit across from each other on a pair of high
翻译加造句
一、翻译 1. The idea of consciously seeking out a special title was new to me., but not without appeal. 让我自己挑选自己最喜欢的书籍这个有意思的想法真的对我具有吸引力。 2.I was plunged into the aching tragedy of the Holocaust, the extraordinary clash of good, represented by the one decent man, and evil. 我陷入到大屠杀悲剧的痛苦之中，一个体面的人所代表的善与恶的猛烈冲击之中。 3.I was astonished by the the great power a novel could contain. I lacked the vocabulary to translate my feelings into words. 我被这部小说所包含的巨大能量感到震惊。我无法用语言来表达我的感情（心情）。 4，make sth. long to short长话短说 5.I learned that summer that reading was not the innocent(简单的) pastime(消遣) I have assumed it to be., not a breezy, instantly forgettable escape in the hammock(吊床)，( though I’ ve enjoyed many of those too ). I discovered that a book, if it arrives at the right moment, in the proper season, will change the course of all that follows. 那年夏天，我懂得了读书不是我认为的简单的娱乐消遣，也不只是躺在吊床上，一阵风吹过就忘记的消遣。我发现如果在适宜的时间、合适的季节读一本书的话，他将能改变一个人以后的人生道路。 二、词组造句 1. on purpose 特意，故意 This is especially true here, and it was ~. (这一点在这里尤其准确，并且他是故意的) 2.think up 虚构，编造，想出 She has thought up a good idea. 她想出了一个好的主意。 His story was thought up. 他的故事是编出来的。 3. in the meantime 与此同时 助记：in advance 事前in the meantime 与此同时in place 适当地... In the meantime, what can you do? 在这期间您能做什么呢？ In the meantime, we may not know how it works, but we know that it works. 在此期间，我们不知道它是如何工作的，但我们知道，它的确在发挥作用。 4.as though 好像，仿佛 It sounds as though you enjoyed Great wall. 这听起来好像你喜欢长城。 5. plunge into 使陷入 He plunged the room into darkness by switching off the light. 他把灯一关，房
改写句子练习2标准答案
The effective sentences:(improve the sentences!) 1.She hopes to spend this holiday either in Shanghai or in Suzhou. 2.Showing/to show sincerity and to keep/keeping promises are the basic requirements of a real friend. 3.I want to know the space of this house and when it was built. I want to know how big this house is and when it was built. I want to know the space of this house and the building time of the house. 4.In the past ten years,Mr.Smith has been a waiter,a tour guide,and taught English. In the past ten years,Mr.Smith has been a waiter,a tour guide,and an English teacher. 5.They are sweeping the floor wearing masks. They are sweeping the floor by wearing masks. wearing masks,They are sweeping the floor. 6.the drivers are told to drive carefully on the radio. the drivers are told on the radio to drive carefully 7.I almost spent two hours on this exercises. I spent almost two hours on this exercises. 8.Checking carefully,a serious mistake was found in the design. Checking carefully,I found a serious mistake in the design.
用以下短语造句
M1 U1 一. 把下列短语填入每个句子的空白处（注意所填短语的形式变化）： add up (to) be concerned about go through set down a series of on purpose in order to according to get along with fall in love (with) join in have got to hide away face to face 1 We’ve chatted online for some time but we have never met ___________. 2 It is nearly 11 o’clock yet he is not back. His mother ____________ him. 3 The Lius ___________ hard times before liberation. 4 ____________ get a good mark I worked very hard before the exam. 5 I think the window was broken ___________ by someone. 6 You should ___________ the language points on the blackboard. They are useful. 7 They met at Tom’s party and later on ____________ with each other. 8 You can find ____________ English reading materials in the school library. 9 I am easy to be with and _____________my classmates pretty well. 10 They __________ in a small village so that they might not be found. 11 Which of the following statements is not right ____________ the above passage? 12 It’s getting dark. I ___________ be off now. 13 More than 1,000 workers ___________ the general strike last week. 14 All her earnings _____________ about 3,000 yuan per month. 二.用以下短语造句： 1.go through 2. no longer/ not… any longer 3. on purpose 4. calm… down 5. happen to 6. set down 7. wonder if 三. 翻译： 1.曾经有段时间，我对学习丧失了兴趣。（there was a time when…） 2. 这是我第一次和她交流。（It is/was the first time that …注意时态） 3.他昨天公园里遇到的是他的一个老朋友。（强调句） 4. 他是在知道真相之后才意识到错怪女儿了。（强调句） M 1 U 2 一. 把下列短语填入每个句子的空白处（注意所填短语的形式变化）： play a …role (in) because of come up such as even if play a …part (in) 1 Dujiangyan(都江堰) is still ___________in irrigation(灌溉) today. 2 That question ___________ at yesterday’s meeting. 3 Karl Marx could speak a few foreign languages, _________Russian and English. 4 You must ask for leave first __________ you have something very important. 5 The media _________ major ________ in influencing people’s opinion s. 6 _________ years of hard work she looked like a woman in her fifties. 二.用以下短语造句： 1.make (good/full) use of 2. play a(n) important role in 3. even if 4. believe it or not 5. such as 6. because of
英语造句
English sentence 1、(1)、able adj. 能 句子：We are able to live under the sea in the future. (2)、ability n. 能力 句子：Most school care for children of different abilities. (3)、enable v. 使。。。能 句子：This pass enables me to travel half-price on trains. 2、(1)、accurate adj. 精确的 句子：We must have the accurate calculation. (2)、accurately adv. 精确地 句子：His calculation is accurately. 3、(1)、act v. 扮演 句子：He act the interesting character.（2）、actor n. 演员 句子：He was a famous actor. (3)、actress n. 女演员 句子：She was a famous actress. (4)、active adj. 积极的 句子：He is an active boy. 4、add v. 加 句子：He adds a little sugar in the milk. 5、advantage n. 优势 句子：His advantage is fight. 6、age 年龄n. 句子：His age is 15. 7、amusing 娱人的adj. 句子：This story is amusing. 8、angry 生气的adj. 句子：He is angry. 9、America 美国n. 句子：He is in America. 10、appear 出现v. He appears in this place. 11. artist 艺术家n. He is an artist. 12. attract 吸引 He attracts the dog. 13. Australia 澳大利亚 He is in Australia. 14.base 基地 She is in the base now. 15.basket 篮子 His basket is nice. 16.beautiful 美丽的 She is very beautiful. 17.begin 开始 He begins writing. 18.black 黑色的 He is black. 19.bright 明亮的 His eyes are bright. 20.good 好的 He is good at basketball. 21.British 英国人 He is British. 22.building 建造物 The building is highest in this city 23.busy 忙的 He is busy now. 24.calculate 计算 He calculates this test well. 25.Canada 加拿大 He borns in Canada. 26.care 照顾 He cared she yesterday. 27.certain 无疑的 They are certain to succeed. 28.change 改变 He changes the system. 29.chemical 化学药品