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Determination of oil content in whole corn seeds by means of near infrared reflectance spectroscopy

Determination of oil content in whole corn  seeds by means of near infrared reflectance spectroscopy
Determination of oil content in whole corn  seeds by means of near infrared reflectance spectroscopy

Application note

Determination of oil content in whole corn (Zea mays L.)seeds by means of near infrared re?ectance

spectroscopy

A.S.Fassio a ,E.A.Restaino a ,D.Cozzolino b ,?

a Instituto Nacional de Investigación Agropecuaria,Estación Experimental INIA La Estanzuela,Ruta 50–km 12,CC 39173Colonia,Uruguay b

School of Agriculture,Food and Wine,The University of Adelaide,Waite Campus,PMB 1Glen Osmond,SA 5064,Australia

a r t i c l e i n f o Article history:

Received 30July 2014

Received in revised form 21October 2014Accepted 15November 2014

Keywords:Near infrared Oil

Partial least squares Re?ectance Corn

a b s t r a c t

The objective of this study was to evaluate the ability of near infrared re?ectance (NIR)spectroscopy to determine oil content in whole corn (Zea mays L.)samples sourced from a breeding program.Kernel sam-ples were analysed in re?ectance in the VIS and NIR regions (400–2500nm)at 2nm intervals using a scanning monochromator.Samples were scanned in a circular cell cup and re?ectance data were stored as logarithm of the reciprocal re?ectance (log 1/R ).Samples were not rotated when spectra collection was made.The coef?cients of determination (R 2)and the standard error of cross validation (SECV)obtained for the prediction of oil content in the calibration set were 0.90%and 0.17%,respectively.The residual predictive deviation (RPD =SD/SECV)value obtained was 2.3,indicating that these calibrations can be used for qualitative determination of oil content (e.g.low,medium and high)or preliminary screening in whole corn.

ó2014Elsevier B.V.All rights reserved.

1.Introduction

The use of rapid and non-invasive techniques to ?ngerprint compositional,physiological or biochemical properties that can be used to assist plant scientists,researchers and farmers to target sustainable agriculture are of paramount importance in modern agriculture (Cabrera-Bosquet et al.,2012;White et al.,2012;Walter et al.,2012).The combination of fundamental research in plant science,multivariate data analysis,and vibrational spectros-copy will enable the development of technologies that will allow the rapid,non-destructive and low-cost testing of plants in the so called high throughput methods (Cabrera-Bosquet et al.,2012;White et al.,2012;Walter et al.,2012).

Understanding how particular genotypes result in speci?c phe-notypic properties is a primary goal of modern biology,enabling the development of new genotypes with commercially useful and adapted characteristics (Abberton and Marshall,2005;White et al.,2012;Walter et al.,2012).However,prediction of the pheno-type or novel plant traits from genotype is generally a dif?cult task due to the large number of genes,as well as the complexity of the interactions with the environment (Cabrera-Bosquet et al.,2012;White et al.,2012;Walter et al.,2012).

The use of routine methods such as standard separation,chro-matographic and spectrometric methods were found useful in chemical analysis as well as in both animal and plant physiology studies for ?ngerprinting and identi?cation of different chemical compounds (Cozzolino,2011;Smyth and Cozzolino,2013).Each of these methods provides unique capabilities to separate different chemical classes of metabolites from several types of samples.At the same time,developments in mathematics,statistics,software and computers have provided algorithms (e.g.principal compo-nent analysis,partial least squares,discriminant analysis)and the computational power that enable the analysis and interpretation of complex data sets generated,in what is called now chemomet-rics (Cozzolino,2011;Smyth and Cozzolino,2013).

Methods based on vibrational spectroscopy such as near infra-red re?ectance (NIR)and mid infrared (MIR)spectroscopy are known to be non-destructive and low cost determining that they can be one of the most appropriate methods or techniques to determine several characteristics or properties in plants (Montes et al.,2007,2011;Cozzolino,2011;Smyth and Cozzolino,2013).Oil content in corn is of importance for breeders where its determination will be of valuable analytical interest for monitoring the success of selective breeding and transgenic engineering pro-grams focused on increasing oil content in a commercial crop (Dunlap et al.,1995;Gambhir,1992;Kotyka et al.,2005).Quanti-tative analysis of oil is achieved using conventional analytical pro-cedures,such as solvent extraction,accelerated solvent extraction (ASE),supercritical ?uid extraction,microwave assisted extraction,and Soxtherm extraction (AOAC,1990;Rubel,1994;Dunlap et al.,1995).Unfortunately,these methods are time consuming,

https://www.wendangku.net/doc/bf11934093.html,/10.1016/https://www.wendangku.net/doc/bf11934093.html,pag.2014.11.0150168-1699/ó2014Elsevier B.V.All rights reserved.

?Corresponding author.

E-mail address:d.cozzolino@https://www.wendangku.net/doc/bf11934093.html,.au (D.Cozzolino).

laborious,and involve hazardous solvents(AOAC,1990;Dunlap et al.,1995;Gambhir,1992;Kotyka et al.,2005).The minimum sample amount required using these methods often prohibit the measurement of single seeds,or at best provide single-seed mea-surements with reduced accuracy and precision(Dunlap et al., 1995;Gambhir,1992;Kotyka et al.,2005).From the breeding point of view these methods destroy the sample for subsequent breeding experiments or for genetic investigations of the heritability of a high-oil trait.The use of both NIR transmission and re?ectance spectroscopy has been reported for the prediction of moisture, oil,protein and starch content in several crop samples including canola and sun?ower where large numbers of seeds need to be analysed(Finney and Norris,1978;Panford and deMan,1990; Orman and Schumann,1991,1992;Daun et al.,1994;Delwiche, 1995;Sato et al.,1998;Velasco et al.,1997,1998,1999a,b; Delwiche and Hruschka,2000;Campbell et al.,2000;Cogdill et al.,2004;Fassio and Cozzolino,2004;Baye et al.,2006a,b; Jiang et al.,2007;Spielbauer et al.,2009;Baranska et al.,2010).

The objective of this study was to evaluate the ability of NIR spectroscopy to determine oil content in whole corn(Zea mays L.)samples sourced from a breeding program.

2.Materials and methods

Experiments were conducted over a period of2consecutive years at La Estanzuela Agricultural Experimental Research Station, INIA La Estanzuela–Uruguay(34°S,57°W).Uruguay is located entirely within the temperate zone,with average high and low temperatures in Summer(January)being28°C and17°C,where in Winter(July)average high and low temperatures are14°C and6°C,respectively.Rainfall is fairly evenly distributed through-out the year with mean annual precipitation of950mm.The experimental farm was located in an Argiudoll,and comprised of a silty clay loam soil.

Commercial varieties and hybrids as well as experimental lines were used in this study.Corn samples were taken from experimen-tal plots where ten plants for each genotype were harvested.Then, kernels were stripped from the corn and combined into a single composite sample.Ether extract(EE)was determined by extracting the sample with petroleum ether according to the Soxhlet method (AOAC,1990).All chemical analysis was expressed on a dry weight basis(%)and analysed in duplicate(error between5%and10%).

Kernel samples(n=256)were analysed in re?ectance in the VIS and NIR regions(400–2500nm)at2nm intervals using a scanning monochromator NIRSystems6500(NIRSystems,Silver Spring,MD, USA).Samples were scanned in a circular cell cup and re?ectance data were stored as logarithm of the reciprocal re?ectance (log1/R).The circular cup was not rotated when spectra collection was made.The spectrum of each sample was the average of32 successive scans(1050data points per scan).Spectral collection and instrument diagnostics were performed using Infrasoft International software(ISI,version 3.01,Infrasoft International, NIRSystems,Silver Spring,MD,USA).Only the NIR region(1100–2500nm)was used for further analysis(calibration development).

Spectra were exported in NSAS format into The Unscrambler X (version10.1,CAMO,Norway)for multivariate analysis.Principal Component Analysis(PCA)was performed before partial least squares regression(PLS)models were developed.Pre-processing was performed using the second derivative achieved with Sav-itzky–Golay transformation and smoothing(2nd order polynomial and20points smoothing)(Duckworth,2004).Standard Normal Variate(SNV)was also used(Barnes et al.,1989).SNV is a row-ori-ented transformation which centres and scales individual spectra (Duckworth,2004).Each value in a row of data is transformed according to the formula,thus the practical result of SNV is that it removes scatter effects from spectral data(Duckworth,2004). PCA was used to examine relevant and interpretable structure in the data as well as outlier detection.Calibration models were developed using PLS with full cross validation(Naes et al.,2002). The optimum number of terms in the PLS calibration models was indicated by the lowest number of factors that gave the minimum value of the prediction residual error sum of squares(PRESS)in cross validation in order to avoid over?tting in the models(Naes et al.,2002).The resulting calibration equations between the refer-ence values and the NIR data were evaluated based on the coef?-cient of determination in calibration(R2cal)and SECV.The ratio of standard deviation(SD)and SECV namely residual predictive value (RPD)were used to test the accuracy of the calibration models (Williams,2001;Fearn,2002).The RPD for the NIR calibration for the parameters evaluated demonstrated how well the calibration models performed in predicting the reference data.If a product shows a narrow range in composition,or if the error in estimation is large compared with the spread(as SD)in composition,then regression?nds increasing dif?culty in?nding stable NIR calibra-tions.An RPD value greater than three was considered adequate for analytical purposes in most of the NIR applications for agricul-tural products(Williams,2001).Samples used for the NIR analysis were selected to represent the whole spectral and chemical variabil-ity in the target population in the calibration and validation groups, respectively.The Mahalanobis distance(H)was used as a criterion for selecting those samples in the population as being more variable on the basis of spectra features(Shenk and Westerhaus,1993).The ISI algorithm CENTER was used to establish population boundaries with a maximum standardised H distance of3.0.Then,the algorithm SELECT was used for ef?cient selection,by choosing samples with a minimum standardised H distance of0.6from their nearest neigh-bours(Shenk and Westerhaus,1993).The value of standardised H selected has been reported to deliver the lowest prediction error during calibration in many NIR applications(Shenk and Westerhaus,1993).Based on this selection128samples were used in the calibration while the other128were used as validation.

3.Results and discussion

The mean,range,standard deviation(SD)and coef?cient of var-iation(CV)for oil content in the corn samples analysed(calibration and validation)are shown in Table1.The samples analysed showed a wide range in oil content as shown by the range(3.1–5.3%)and the CV(9.51)in the calibration set.The mean values and range observed for oil content are in accordance with those reported by other authors(Tallada et al.,2009;Baye et al., 2006a,b;Jiang et al.,2007;Spielbauer et al.,2009).The chemical composition of the samples showed a wide range in composition due to the different genotypes(varieties and hybrids)analysed. The variability in oil composition between the different samples was considered suitable to develop NIR calibrations.

A PCA was derived from the spectral data to visualise distribu-tion and structure of the samples in the data set.Fig.1shows the ?rst two principal components that explain96%of the variation in the NIR spectra of the corn samples analysed.No clear separation was observed between samples either related with harvest or genotype(hybrids,varieties and experimental lines).However,

Table1

Descriptive statistics for oil(%)content in whole kernel samples.

Mean SD Range CV

Calibration(n=128) 4.310.41 3.1–5.39.51 Validation(n=128) 4.270.48 2.9–5.611.2

SD:standard deviation,CV:coef?cient of variation.

172 A.S.Fassio et al./Computers and Electronics in Agriculture110(2015)171–175

A.S.Fassio et al./Computers and Electronics in Agriculture110(2015)171–175173

First principal component

Score plot of the?rst two principal components of corn samples measured using near infrared re?ectance spectroscopy.

Table2

Cross validation statistics for the measurement of oil content(%)in corn samples using near infrared re?ectance spectroscopy.

R2SECV SEP Bias Slope RPD PLS terms

Calibration(n=128)0.920.170.00160.84 2.415 Validation(n=128)0.900.210.0180.80 2.3

R2:coef?cient of determination in cross validation,SECV:standard error of cross validation;RPD:SD/SECV,SEP=standard error of prediction.

Oil% reference

Predicted values versus reference values for the measurement of oil content in corn using near infrared re?ectance spectroscopy.

some spectroscopic outlier samples were observed.The?rst PC explains89%of the total variance in the samples,and the highest eigenvectors were found around1192nm,at1456nm associated with O A H absorption bands(second overtone),at1928nm with O A H?rst overtone,at2234nm and at2312and2342nm related to C A H and C@C tones,respectively(Workman and Weyer, 2008).This spectral region might be also characteristic of?bre fractions such as cellulose(Workman and Weyer,2008).The sec-ond PC explains7%of the variation and the highest eigenvectors were found around1666nm and1724nm both related to aromatic hydrocarbons and C A H?rst overtones and at2248related with either C A H and N A H combinations combination and deformations associated with carbohydrates and proteins(Workman and Weyer, 2008).

Cross validation statistics for the PLS models(n=128)devel-oped for the measurement of oil content in the calibration set are shown in Table2.The coef?cients of determination in cross val-idation(R2)and the standard error of cross validation(SECV)for oil content were0.90and0.17%,respectively.The R2obtained indi-cated that90%of the variance in oil content in the set of corn sam-ples analysed is accounted by the NIR spectra.In addition,the R2is considered adequate for screening and for approximate calibration (Williams,2001;Fearn,2002).The RPD value obtained for oil con-tent was2.3,indicating that these calibrations can be used for qualitative determination of oil content(e.g.low,medium and high)and might be considered adequate for screening samples for this parameter(Williams,2001;Fearn,2002).The SEP value (0.21%)obtained in the validation set indicated that the PLS cali-bration models are adequate for a large scale screening of corn samples.These results(SEP and RPD)were better than those reported by other authors(Tallada et al.,2009;Baye et al., 2006a,b;Jiang et al.,2007;Spielbauer et al.,2009).In most of the previous studies single kernel samples were used.In this study between10and12single kernels were packed together in the cir-cular cell during scanning.

A graphical comparison of oil content determined by the refer-ence method and the predicted NIR data in validation is shown in Fig.2.The more accurate the predictive models,the more closely all points cluster near the theoretical1:1correspondence shown by the solid line(Williams,2001).Validation samples that display more scatter about this line resulting in higher standard error val-ues in validation.

Examination of the loadings derived from the PLS calibration models might provide insights into the main NIR regions associ-ated with the chemical parameter measured.Loadings are also used to determine which wavelengths are important in order to describe the main sources of variation in the data set.They can also be used to determine the inherent dimensionality of the data set as well as to identify unusual variables(Beebe et al.,1998).In this study,the loadings were used to identify the most important NIR regions that describe the main variation for the optimal PLS cali-bration models(5terms)developed for oil content in corn.Fig.3 shows the PLS loadings derived from the optimal calibration model developed for the measurement of oil content in corn.The highest negative loadings were observed at absorption bands around 1500nm and1900nm associated with O A H overtones(mainly water).Positive loadings were observed between1700and 1740nm associated with CH2and CH3(lipids),between2100and 2300nm associated with C A H overtones and combination bands of carbohydrates,lipids and proteins(Workman and Weyer,2008).

4.Conclusion

The results from this study showed that oil content can be pre-dicted using NIR spectroscopy in whole corn samples.Further work will be carried out including a broader range of sample types in order to test the robustness of the calibration models obtained. We also have demonstrated that more research is needed in order to develop a reliable NIR calibration model for oil content. Acknowledgements

The authors thank the technicians of the Summer Crop Pro-gram,Animal Nutrition and Grain Labs at INIA La Estanzuela–Colonia(Uruguay).This work was supported by INIA–Uruguay. References

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英语中的比较级与最高级 详解

比较级与最高级 1.as...as 与(not) as(so)...as as...as...句型中,as的词性 第一个as是副词,用在形容词和副词的原级前,常译为“同样地”。第二个as是连词,连接与前面句子结构相同的一个句子(相同部分常省略),可译为“同..... He is as tall as his brother is (tall) . (后面的as 为连词) 只有在否定句中,第一个as才可换为so 改错: He is so tall as his brother.(X) 2.在比较状语从句中,主句和从句的句式结构一般是相同的 与as...as 句式中第二个as一样,than 也是连词。as和than这两个连词后面的从句的结构与前面的句子大部分情况下结构是相同的,相同部分可以省略。 He picked more apples than she did. 完整的表达为: He picked more apples than she picked apples. 后而的picked apples和前面相同,用did 替代。 He walked as slowly as she did.完整表达为: He walked as slowly as she walked slowly. she后面walked slowly与前面相同,用did替代。

3.谓语的替代 在as和than 引导的比较状语从句中,由于句式同前面 主句相同,为避免重复,常把主句中出现而从句中又出现的动词用do的适当形式来代替。 John speaks German as fluently as Mary does. 4.前后的比较对象应一致 不管后面连词是than 还是as,前后的比较对象应一致。The weather of Beijing is colder than Guangzhou. x than前面比较对象是“天气”,than 后面比较对象是“广州”,不能相比较。应改为: The weather of Bejing is colder than that of Guangzhou. 再如: His handwriting is as good as me. 应改为: His handwriting is as good as mine. 5.可以修饰比较级的词 常用来修饰比较级的词或短语有: Much,even,far,a little,a lot,a bit,by far,rather,any,still,a great deal等。 by far的用法: 用于强调,意为“...得多”“最最...”“显然”等,可修饰形容词或副词的比较级和最高级,通常置于其后,但是若比较级或最高级前有冠词,则可置于其前或其后。

The way常见用法

The way 的用法 Ⅰ常见用法: 1)the way+ that 2)the way + in which(最为正式的用法) 3)the way + 省略(最为自然的用法) 举例:I like the way in which he talks. I like the way that he talks. I like the way he talks. Ⅱ习惯用法: 在当代美国英语中,the way用作为副词的对格,“the way+ 从句”实际上相当于一个状语从句来修饰整个句子。 1)The way =as I am talking to you just the way I’d talk to my own child. He did not do it the way his friends did. Most fruits are naturally sweet and we can eat them just the way they are—all we have to do is to clean and peel them. 2)The way= according to the way/ judging from the way The way you answer the question, you are an excellent student. The way most people look at you, you’d think trash man is a monster. 3)The way =how/ how much No one can imagine the way he missed her. 4)The way =because

人教版(新目标)初中英语形容词与副词的比较级与最高级

人教版(新目标)初中英语形容词与副词的比较级与最高级 (一)规则变化: 1.绝大多数的单音节和少数双音节词,加词尾-er ,-est tall—taller—tallest 2.以不发音的e结尾的单音节词和少数以-le结尾的双音节词只加-r,-st nice—nicer—nicest , able—abler—ablest 3.以一个辅音字母结尾的重读闭音节词或少数双音节词,双写结尾的辅音字母,再加-er,-est big—bigger—biggest 4.以辅音字母加y结尾的双音节词,改y为i再加-er,-est easy—easier—easiest 5.少数以-er,-ow结尾的双音节词末尾加-er,-est clever—cleverer—cleverest, narrow—narrower—narrowest 6.其他双音节词和多音节词,在前面加more,most来构成比较级和最高级 easily—more easily—most easily (二)不规则变化 常见的有: good / well—better—best ; bad (ly)/ ill—worse—worst ; old—older/elder—oldest/eldest many / much—more—most ; little—less—least ; far—farther/further—farthest/furthest

用法: 1.原级比较:as + adj./adv. +as(否定为not so/as + adj./adv. +as)当as… as中间有名字时,采用as + adj. + a + n.或as + many / much + n. This is as good an example as the other is . I can carry as much paper as you can. 表示倍数的词或其他程度副词做修饰语时放在as的前面 This room is twice as big as that one. 倍数+as+adj.+as = 倍数+the +n.+of Your room is twice as larger as mine. = Your room is twice the size of mine. 2.比较级+ than 比较级前可加程度状语much, still, even, far, a lot, a little, three years. five times,20%等 He is three years older than I (am). 表示“(两个中)较……的那个”时,比较级前常加the(后面有名字时前面才能加冠词) He is the taller of the two brothers. / He is taller than his two brothers. Which is larger, Canada or Australia? / Which is the larger country, Canada or Australia? 可用比较级形式表示最高级概念,关键是要用或或否定词等把一事物(或人)与其他同类事物(或人)相分离 He is taller than any other boy / anybody else.

英语中的比较级和最高级

大多数形容词有三种形式,原级,比较级和最高级, 以表示形容词说明的性质在程度上的不同。 形容词的原级: 形容词的原级形式就是词典中出现的形容词的原形。例如: poor tall great glad bad 形容词的比较级和最高级: 形容词的比较级和最高级形式是在形容词的原级形式的基础上变化的。分为规则变化和不规则变化。 规则变化如下: 1) 单音节形容词的比较级和最高级形式是在词尾加 -er 和 -est 构成。 great (原级) (比较级) (最高级) 2) 以 -e 结尾的单音节形容词的比较级和最高级是在词尾加 -r 和 -st 构成。wide (原级) (比较级) (最高级) 3)少数以-y, -er, -ow, -ble结尾的双音节形容词的比较级和最高级是在词尾加 -er 和 -est 构成。 clever(原级) (比较级) (最高级) 4) 以 -y 结尾,但 -y 前是辅音字母的形容词的比较级和最高级是把 -y 去掉,加上 -ier 和-est 构成. happy (原形) (比较级) (最高级) 5) 以一个辅音字母结尾其前面的元音字母发短元音的形容词的比较级和最高级是双写该辅音字母然后再加 -er和-est。 big (原级) (比较级) (最高级) 6) 双音节和多音节形容词的比较级和最高级需用more 和 most 加在形容词前面来构成。 beautiful (原级) (比较级) (比较级) difficult (原级) (最高级) (最高级) 常用的不规则变化的形容词的比较级和最高级: 原级------比较级------最高级 good------better------best many------more------most much------more------most bad------worse------worst far------farther, further------farthest, furthest 形容词前如加 less 和 least 则表示"较不"和"最不 形容词比较级的用法: 形容词的比较级用于两个人或事物的比较,其结构形式如下: 主语+谓语(系动词)+ 形容词比较级+than+ 对比成分。也就是, 含有形容词比较级的主句+than+从句。注意从句常常省去意义上和主句相同的部分, 而只剩下对比的成分。

The way的用法及其含义(二)

The way的用法及其含义(二) 二、the way在句中的语法作用 the way在句中可以作主语、宾语或表语: 1.作主语 The way you are doing it is completely crazy.你这个干法简直发疯。 The way she puts on that accent really irritates me. 她故意操那种口音的样子实在令我恼火。The way she behaved towards him was utterly ruthless. 她对待他真是无情至极。 Words are important, but the way a person stands, folds his or her arms or moves his or her hands can also give us information about his or her feelings. 言语固然重要,但人的站姿,抱臂的方式和手势也回告诉我们他(她)的情感。 2.作宾语 I hate the way she stared at me.我讨厌她盯我看的样子。 We like the way that her hair hangs down.我们喜欢她的头发笔直地垂下来。 You could tell she was foreign by the way she was dressed. 从她的穿著就可以看出她是外国人。 She could not hide her amusement at the way he was dancing. 她见他跳舞的姿势,忍俊不禁。 3.作表语 This is the way the accident happened.这就是事故如何发生的。 Believe it or not, that's the way it is. 信不信由你, 反正事情就是这样。 That's the way I look at it, too. 我也是这么想。 That was the way minority nationalities were treated in old China. 那就是少数民族在旧中

英语比较级和最高级的用法归纳

英语比较级和最高级的用法归纳 在学习英语过程中,会遇到很多的语法问题,比如比较级和最高级的用法,对于 这些语法你能够掌握吗?下面是小编整理的英语比较级和最高级的用法,欢迎阅读! 英语比较级和最高级的用法 一、形容词、副词的比较级和最高级的构成规则 1.一般单音节词和少数以-er,-ow结尾的双音节词,比较级在后面加-er,最高级 在后面加-est; (1)单音节词 如:small→smaller→smallest short→shorter→shortest tall→taller→tallest great→greater→greatest (2)双音节词 如:clever→cleverer→cleverest narrow→narrower→narrowest 2.以不发音e结尾的单音节词,比较在原级后加-r,最高级在原级后加-st; 如:large→larger→largest nice→nicer→nicest able→abler→ablest 3.在重读闭音节(即:辅音+元音+辅音)中,先双写末尾的辅音字母,比较级加-er,最高级加-est; 如:big→bigger→biggest hot→hotter→hottest fat→fatter→fattest 4.以“辅音字母+y”结尾的双音节词,把y改为i,比较级加-er,最高级加-est; 如:easy→easier→easiest heavy→heavier→heaviest busy→busier→busiest happy→happier→happiest 5.其他双音节词和多音节词,比较级在前面加more,最高级在前面加most; 如:bea utiful→more beautiful→most beautiful different→more different→most different easily→more easily→most easily 注意:(1)形容词最高级前通常必须用定冠词 the,副词最高级前可不用。 例句: The Sahara is the biggest desert in the world. (2) 形容词most前面没有the,不表示最高级的含义,只表示"非常"。 It is a most important problem. =It is a very important problem.

(完整版)the的用法

定冠词the的用法: 定冠词the与指示代词this ,that同源,有“那(这)个”的意思,但较弱,可以和一个名词连用,来表示某个或某些特定的人或东西. (1)特指双方都明白的人或物 Take the medicine.把药吃了. (2)上文提到过的人或事 He bought a house.他买了幢房子. I've been to the house.我去过那幢房子. (3)指世界上独一无二的事物 the sun ,the sky ,the moon, the earth (4)单数名词连用表示一类事物 the dollar 美元 the fox 狐狸 或与形容词或分词连用,表示一类人 the rich 富人 the living 生者 (5)用在序数词和形容词最高级,及形容词等前面 Where do you live?你住在哪? I live on the second floor.我住在二楼. That's the very thing I've been looking for.那正是我要找的东西. (6)与复数名词连用,指整个群体 They are the teachers of this school.(指全体教师) They are teachers of this school.(指部分教师) (7)表示所有,相当于物主代词,用在表示身体部位的名词前 She caught me by the arm.她抓住了我的手臂. (8)用在某些有普通名词构成的国家名称,机关团体,阶级等专有名词前 the People's Republic of China 中华人民共和国 the United States 美国 (9)用在表示乐器的名词前 She plays the piano.她会弹钢琴. (10)用在姓氏的复数名词之前,表示一家人 the Greens 格林一家人(或格林夫妇) (11)用在惯用语中 in the day, in the morning... the day before yesterday, the next morning... in the sky... in the dark... in the end... on the whole, by the way...

英语比较级和最高级的用法

More than的用法 A. “More than+名词”表示“不仅仅是” 1)Modern science is more than a large amount of information. 2)Jason is more than a lecturer; he is a writer, too. 3) We need more than material wealth to build our country.建设我们国家,不仅仅需要物质财富. B. “More than+数词”含“以上”或“不止”之意,如: 4)I have known David for more than 20 years. 5)Let's carry out the test with more than the sample copy. 6) More than one person has made this suggestion. 不止一人提过这个建议. C. “More than+形容词”等于“很”或“非常”的意思,如: 7)In doing scientific experiments, one must be more than careful with the instruments. 8)I assure you I am more than glad to help you. D. more than + (that)从句,其基本意义是“超过(=over)”,但可译成“简直不”“远非”.难以,完全不能(其后通常连用情态动词can) 9) That is more than I can understand . 那非我所能懂的. 10) That is more than I can tell. 那事我实在不明白。 11) The heat there was more than he could stand. 那儿的炎热程度是他所不能忍受的 此外,“more than”也在一些惯用语中出现,如: more...than 的用法 1. 比……多,比……更 He has more books than me. 他的书比我多。 He is more careful than the others. 他比其他人更仔细。 2. 与其……不如 He is more lucky than clever. 与其说他聪明,不如说他幸运。 He is more (a)scholar than (a)teacher. 与其说他是位教师,不如说他是位学者。 注:该句型主要用于同一个人或物在两个不同性质或特征等方面的比较,其中的比较级必须用加more 的形式,不能用加词尾-er 的形式。 No more than/not more than 1. no more than 的意思是“仅仅”“只有”“最多不超过”,强调少。如: --This test takes no more than thirty minutes. 这个测验只要30分钟。 --The pub was no more than half full. 该酒吧的上座率最多不超过五成。-For thirty years,he had done no more than he (had)needed to. 30年来,他只干了他需要干的工作。 2. not more than 为more than (多于)的否定式,其意为“不多于”“不超过”。如:Not more than 10 guests came to her birthday party. 来参加她的生日宴会的客人不超过十人。 比较: She has no more than three hats. 她只有3顶帽子。(太少了) She has not more than three hats. 她至多有3顶帽子。(也许不到3顶帽子) I have no more than five yuan in my pocket. 我口袋里的钱最多不过5元。(言其少) I have not more than five yuan in my pocket. 我口袋里的钱不多于5元。(也许不到5元) more than, less than 的用法 1. (指数量)不到,不足 It’s less than half an hour’s drive from here. 开车到那里不到半个钟头。 In less than an hour he finished the work. 没要上一个小时,他就完成了工作。 2. 比……(小)少 She eats less than she should. 她吃得比她应该吃的少。 Half the group felt they spent less than average. 半数人觉得他们的花费低于平均水平。 more…than,/no more than/not more than (1)Mr.Li is ________ a professor; he is also a famous scientist. (2)As I had ________ five dollars with me, I couldn’t afford the new jacket then. (3)He had to work at the age of ________ twelve. (4)There were ________ ten chairs in the room.However, the number of the children is twelve. (5)If you tel l your father what you’ve done, he’ll be ________ angry. (6)-What did you think of this novel? -I was disappointed to find it ________ interesting ________ that one. 倍数表达法 1. “倍数+形容词(或副词)的比较级+than+从句”表示“A比B大(长、高、宽等)多少倍” This rope is twice longer than that one.这根绳是那根绳的三倍(比那根绳长两倍)。The car runs twice faster than that truck.这辆小车的速度比那辆卡车快两倍(是那辆卡车的三倍)。 2. “倍数+as+形容词或副词的原级+as+从句”表示“A正好是B的多少倍”。

“the way+从句”结构的意义及用法

“theway+从句”结构的意义及用法 首先让我们来看下面这个句子: Read the followingpassageand talkabout it wi th your classmates.Try totell whatyou think of Tom and ofthe way the childrentreated him. 在这个句子中,the way是先行词,后面是省略了关系副词that或in which的定语从句。 下面我们将叙述“the way+从句”结构的用法。 1.the way之后,引导定语从句的关系词是that而不是how,因此,<<现代英语惯用法词典>>中所给出的下面两个句子是错误的:This is thewayhowithappened. This is the way how he always treats me. 2.在正式语体中,that可被in which所代替;在非正式语体中,that则往往省略。由此我们得到theway后接定语从句时的三种模式:1) the way+that-从句2)the way +in which-从句3) the way +从句 例如:The way(in which ,that) thesecomrade slookatproblems is wrong.这些同志看问题的方法

不对。 Theway(that ,in which)you’re doingit is comple tely crazy.你这么个干法,简直发疯。 Weadmired him for theway inwhich he facesdifficulties. Wallace and Darwingreed on the way inwhi ch different forms of life had begun.华莱士和达尔文对不同类型的生物是如何起源的持相同的观点。 This is the way(that) hedid it. I likedthe way(that) sheorganized the meeting. 3.theway(that)有时可以与how(作“如何”解)通用。例如: That’s the way(that) shespoke. = That’s how shespoke.

初中英语比较级和最高级讲解与练习

初中英语比较级和最高级讲解与练习 形容词比较级和最高级 一.绝大多数形容词有三种形式,原级,比较级和最高级, 以表示形容词说明的性质在程度上的不同。 1. 形容词的原级: 形容词的原级形式就是词典中出现的形容词的原形。例如: poor tall great glad bad 2. 形容词的比较级和最高级: 形容词的比较级和最高级形式是在形容词的原级形式的基 础上变化的。分为规则变化和不规则变化。 二.形容词比较级和最高级规则变化如下: 1) 单音节形容词的比较级和最高级形式是在词尾加-er 和-est 构成。 great (原级) greater(比较级) greatest(最高级) 2) 以-e 结尾的单音节形容词的比较级和最高级是在词尾加-r 和-st 构成。 wide (原级) wider (比较级) widest (最高级) 3) 少数以-y, -er, -ow, -ble结尾的双音节形容词的比较级和最高级是在词尾加 -er 和-est构成。 clever(原级) cleverer(比较级) cleverest(最高级), slow(原级) slower(比较级) slowest (最高级) 4) 以-y 结尾,但-y 前是辅音字母的形容词的比较级和最高级是把-y 去掉,加上-ier 和-est 构成. happy (原形) happier (比较级) happiest (最高级) 5) 以一个辅音字母结尾其前面的元音字母发短元音的形容词的比较级和最高级是双写该 辅音字母然后再加-er和-est。 原形比较级最高级原形比较级最高级 big bigger biggest hot hotter hottest red redder reddest thin thinner thinnest 6) 双音节和多音节形容词的比较级和最高级需用more 和most 加在形容词前面来构 成。 原形比较级最高级 careful careful more careful most careful difficult more difficult most difficult delicious more delicious most delicious 7)常用的不规则变化的形容词的比较级和最高级: 原级比较级最高级 good better best 好的 well better best 身体好的 bad worse worst 坏的 ill worse worst 病的 many more most 许多 much more most 许多 few less least 少数几个 little less least 少数一点儿 (little littler littlest 小的) far further furthest 远(指更进一步,深度。亦可指更远) far farther farthest 远(指更远,路程)

way 用法

表示“方式”、“方法”,注意以下用法: 1.表示用某种方法或按某种方式,通常用介词in(此介词有时可省略)。如: Do it (in) your own way. 按你自己的方法做吧。 Please do not talk (in) that way. 请不要那样说。 2.表示做某事的方式或方法,其后可接不定式或of doing sth。 如: It’s the best way of studying [to study] English. 这是学习英语的最好方法。 There are different ways to do [of doing] it. 做这事有不同的办法。 3.其后通常可直接跟一个定语从句(不用任何引导词),也可跟由that 或in which 引导的定语从句,但是其后的从句不能由how 来引导。如: 我不喜欢他说话的态度。 正:I don’t like the way he spoke. 正:I don’t like the way that he spoke. 正:I don’t like the way in which he spoke. 误:I don’t like the way how he spoke. 4.注意以下各句the way 的用法: That’s the way (=how) he spoke. 那就是他说话的方式。 Nobody else loves you the way(=as) I do. 没有人像我这样爱你。 The way (=According as) you are studying now, you won’tmake much progress. 根据你现在学习情况来看,你不会有多大的进步。 2007年陕西省高考英语中有这样一道单项填空题: ——I think he is taking an active part insocial work. ——I agree with you_____. A、in a way B、on the way C、by the way D、in the way 此题答案选A。要想弄清为什么选A,而不选其他几项,则要弄清选项中含way的四个短语的不同意义和用法,下面我们就对此作一归纳和小结。 一、in a way的用法 表示:在一定程度上,从某方面说。如: In a way he was right.在某种程度上他是对的。注:in a way也可说成in one way。 二、on the way的用法 1、表示:即将来(去),就要来(去)。如: Spring is on the way.春天快到了。 I'd better be on my way soon.我最好还是快点儿走。 Radio forecasts said a sixth-grade wind was on the way.无线电预报说将有六级大风。 2、表示:在路上,在行进中。如: He stopped for breakfast on the way.他中途停下吃早点。 We had some good laughs on the way.我们在路上好好笑了一阵子。 3、表示:(婴儿)尚未出生。如: She has two children with another one on the way.她有两个孩子,现在还怀着一个。 She's got five children,and another one is on the way.她已经有5个孩子了,另一个又快生了。 三、by the way的用法

英语比较级和最高级

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