条件状语从句

外研版第四册模块3 语法: 条件状语从句

Step 1 Presentation

Look at these sentences from the passage.

If you say the word “ communication”, most people think of words and sentences. We use “ learned” body language when we are introduced to strangers.

Now tick the true statements.

The sentences from the passage.

1.describe common situations.

2.describe impossible situation.

https://www.wendangku.net/doc/7713623325.html,e if or when to introduce the situation.

4.explain the result of the situation in the other part of the sentence.

https://www.wendangku.net/doc/7713623325.html,e the present simple tense in both parts of the sentence.

The key: 1,3,4,5

Step 2

我们知道,引导条件状语从句最常用的连词是if,由if引导的条件状语从句表示在某种条件下某事很可能发生。如:

If you ask him, he will help you.如果你请他帮忙,他会帮你的。

If you fail in the exam, you will let him down.如果你考试不及格,你会让他失望的。

另外,if从句还表示不可实现的条件或根本不可能存在的条件,也就是一种虚拟的条件或假设,从句多用一般过去时或过去完成时。如:

If I were you, I would invite him to the party.如果我是你,我会邀请他参加聚会。

I would have arrived much earlier if I had not been caught in the traffic.如果没有堵车,我会到的早一点儿。

那么,除了if之外,是否还有其他连词也可以引导条件状语从句呢?回答是肯定的,不仅有,还有很多。这些词由于出现的频率较小,且用法较复杂一些,所以不如if为大家所熟知罢了。下面就这些词的用法以例句的形式进行一下简单总结。

1. unless conj.除非,若不,除非在……的时候

Y ou will fail to arrive there in time unless you start earlier.如果你不早点动身,你就不能及时赶到那儿。

Unless it rains, the game will be played.除非下雨,比赛将照常进行。

2. on condition(that)...在……条件下,如果

on condition (that)...引导的条件从句是主句事件发生的前提条件或唯一条件。

I can tell you the truth on condition that you promise to keep a secret.我可以告诉你真相,条件是你答应保守秘密。

Y ou can go swimming on condition (that) you don't go too far from the river bank.你只有在不远离河岸的条件下才可以下水游泳。

3. supposing conj.如果,假如

supposing引导的条件从句表示一种假设条件。

Supposing it rains, shall we continue the sports meeting?倘若下雨,我们的运动会还要继续举行吗?

Supposing something should go wrong, what would you do then?假如出了什么问题,你准备怎么对付?

4. provided conj.假如,除非,以……为条件

provided (that) +从句表示一种假设条件。

He will sign the contract provided we offer more favorable terms.如果我们提出更优惠的条件,他就会在合同上签字。

He won't be against us in the meeting provided that we ask for his advice in advance.如果我们提前征求一下他的意见,他就不会在会上反对我们。

另外还有in case, as/so long as

In case it rains, do not expect me. 如若下雨，就不要等我了。

As long as you promise to come, I’ll wait for you until you come.

只要你答应，我就等你来。

从上述例句可以看出if, unless, on condition (that), supposing, provided等词引导的条件状语从句,主从句条件关系分明,结构清晰。在条件状语从句中，用一般现在时代替一般将来时，一般过去时代替过去将来时。但有些句子,虽没有含条

件关系的连词,却也隐含着条件关系,这些句子常用一些词,如but for, without等引出一个介词结构来表示条件,条件常常是虚拟的,或与事实相反的假设。如: but for若非,要不是

But for the rain, we should have a pleasant journey.要不是下雨,我们的旅行肯定会很愉快。

But for your help, we should not have finished in time.要不是你帮忙,我们肯定不能及时完成任务。

Step 3

Find more examples of sentences with if or when in the passage.

The key:

1) If our right hand is busy greeting someone, it cannot be holding a weapon.

2) If you shake hands with someone, you show you trust them.

3) We shake hands when we make a deal.

4) When we greet someone, we put the right hand over the left and bow slightly. Step 4

Match the two parts of these sentences about body language in Europe or America.

1.When you meet someone for the first time. A. you usually mean no.

2.If you say goodbye to someone B. you usually point

3.When you show someone the way C. you often wave to learn

4.If you nod your head D. you don’t take your shoes off

5.When you enter a house E. you shake hands with them

6.If you shake your head F. you usually mean yes.

The key: 1) E 2) C 3) B 4) F 5) D 6) A

Step 5

Grammar 2

Look at the sentences and answer the question

a.if you meet someone you usually shake his/her hand.

b.What shall I do if I’m invited to dinner?

c.Unless you’re very unlucky you’ll soon think of something.

1.Which sentences refers to a normal everyday situation?

2.Which sentences refers to a possibility in the future?

3.Which word in the third sentence mean if …not?

The key: 1.a 2. b 3. unless

Step 6

Complete the sentences with the correct from of verbs in brackets. Example:

If I see her I’ll invite her to the party.( see, invite)

1.If you ________ a cake your host ______ very pleased. ( take, be)

2.Unless the weather __________ better, I________ at home. ( get, stay)

3.He _____ home early if he _________ well. (go, not feel)

4.What ______ I __________ if they _______ about politics?.( do, talk)

5.If you ________ your hand, the taxi__________ (raise, stop)

6.I __________ anything unless he _________ me. ( not stay, ask) Answers:

1)take, will be 2) gets, I’ll stay 3) will go. doesn’t feel 4) shall, do, talk 5) raise, will stop 6) will not say, asks.