大学英语语法专题(1)

一、情态动词

1．could have done sth 表示过去可能完成却未完成的动作

e.g. Judging from what you said, he could have done this work still better.

2. cannot/could not have done sth 表示对过去情况的猜测，“不可能做过某事”。

e.g. This composition is too good; she can’t have written it hersel

f.

3. may/might as well do sth 表示建议，“还是……好”、“还不如……”

e.g. If you don’t like to swim, you may as well stay at home.

4. may/might have done sth 表示对过去事情的猜测，“可能已经……”

e.g. He may have been waiting for us for an hour.

5.mustn’t 表示禁止

don’t have to 表示不必

6.must be 表示对现在情况的推测，“一定是……”

e.g. He must be ill. He looks so pale.

7.must have done sth 表示对过去事情进行的推测，“想必一定……”

e.g. It must have been raining all the night. There are big puddles in the garden.

8.needn’t have done sth 表示过去做了不必要的事

e.g. That’s all settled. It needn’t be talked about.

9. didn’t need to do sth 表示不必做，实际上没有做

e.g. You did not need to come for the group meeting ,so we didn’t inform you.

1. If I were the President, I should/would declare November 1a national holiday.

2.One investigation showed that 40% of those killed in auto accidents could have been saved if they have been wearing seat belts.

3. If you did that again, we would n’t allow you to work with us.

注意：

1．区别if引导的真实条件句：If it doesn't rain tomorrow，we will go there by bike.(主将从现)

2. 错综时间条件句

e.g. 1)If he had got up earlier, he would not be late now.(从句说过去，主句说现在)

2)If we hadn’t been working hard in the past few years, things wouldn’t be going smoothly now.(从句说过去，主句说现在)

3.条件句中的谓语如果含有were, had, should, 从句可省略if, 同时助动词倒装至主语前。

e.g. 1) Were there no gravity(=If there were no gravity), there would be no air around the earth.

2)Should they(=If they should)have forgotten to bring a compass with them, they would have got lost in the woods.

3)Were it not for(=If it were not for)the rain, we could play football now.

4)Had it not been for(=If it hadn’t been for)your help, I would have died.

4.if only(要是……就好了，用来引导虚拟条件从句，表达强烈的愿望和遗憾)

e.g. If only I had more money, I could buy some new books.

only if(只有在……条件下，不用虚拟语气，当它至于句首时，主句要倒装)

e.g. Only if you help me can I succeed.

5.for fear that, lest, in case(以免)等引导的目的状语从句须用虚拟语气，从句中使用“should+动词原形”，should 也可省略。

e.g.1)He did not enter for fear that he(should)interfere with us.

2) Batteries are kept in dry places in case electricity(should)leak away.

若in case表示“如果、即使”，引导真实条件从句时，用陈述语气。

e.g. In case they are late, we can always sit in the bar.

6.It’s(about/high)time…sb. did sth.表示“是该……的时候了”，用一般过去式表示虚拟。

e.g. It is high time that a doctor were sent for.

三、从句

（一）名词性从句

1.主语从句

That our team is weaker is an obvious fact.(that只起连接作用)

Which plan is better is clear now.

It is strange that the children are so quiet.

注意：

Whatever(=anything that)was said here must be kept secret.

Whoever(=anyone who)doesn’t agree can come to me after the meeting.

2.表语从句

The problem is who we can get to replace her.

The truth is that he heated us.

The reason why he was late was that his bike broke down on the way to school.(当主句中的主语是reason, cause或由why引导的主语从句时，表语从句用that,而不能用because。在It/That/This is because…的句型中，可以用because。)

3.宾语从句

I don’t care whether she will come or not.

You get out of life what(=the things that)you put in.

I will give it to whoever(=anyone who)needs it.

I’m glad that you can come.(be+adj+clause)

4.同位语从句（一般跟在一些名词后面，用以说明该名词表示的具体内容，多用that引导，可以跟的名词有answer, belief, decision, evidence, fact, idea, message, news, opinion, problem, truth, thought, etc.）

I had no idea that you were here.

注意：

The news that our team won inspired all of us.(同从，that不担任从句成分)

What’s the news that upset her so much?(定从，that作主语)

（二）定语从句

引导词：关系代词who, whom, whose, which, that, as, but和关系副词when, where, why, that 1.This is the classroom where I first met him.

This is the classroom that we are to clean today.

2.若先行词是all, much, anything, something, noting, everything, little, none等不定代词，关

系代词多用that,而不是which。先行词签有形容词最高级、序数词或only, very, none, no, little, few, much等修饰时，也用that。

e.g. Is there anything that you want to explain?

This is the only reason that I can think of.

He was one of the greatest writers that had ever lived.

3.Way后面的定语从句三种情况：正式文体用in which；一般情况用that；省去in which

和that。

e.g. I was struck by the beauty of the way in which she stood.

There is one way that you could stop others talking about you.

That’s the way I looked at it.

4.As常用于such…as, the same…as, so…as等固定搭配中。

e.g. I have the same trouble as you have.

We will give you such data as will help you in your work.

I don’t think it is so difficult a problem as no one can solve.

5.As 和which都可以引导非限制性定语从句，但as可置于句首，而which不能，而且as 仍然具有“正如….一样”的语义。

e.g. As I knew from his accent, he was a foreigner.

He said he was busy, which was untrue.

6.But作为关系代词，但仅与具有否定意义的主句连用，可以指人也可以指物，相当于

who/that/which….not。

e.g. There are very few but(=who don’t)admire his talent.

There is no rule but has(=that doesn’t have)exceptions.

7.关系代词在定语从句中作介词宾语时，介词既可置于从句之首，也可之末，但前者较为

正式。

e.g.This is the book for which you asked.= This is the book which/that you asked for.(介词+which)

8.限制性和非限制性定语从句

He will wear no clothes which will distinguish him from his fellow men.

He will wear no clothes, which will distinguish him from his fellow men.

9.He is no longer the man that he was before.(the man 就是从句主语he，句子的语意侧重于“他现在的个人特点”，而不是“他是谁”。

He is the man who/whom we are looking for.

（三）状语从句

1.时间状语从句(as, after, before, when, while, as soon as, etc.)

No sooner…than, Hardly…when, The moment/minute/second/instant

e.g.I’ll call you when I get there.

2.地点状语从句（where, wherever, etc）

Where there is a will, there is a way.

3.原因状语从句（because, since, as, for, seeing that, now that, etc.）

We can’t go for it is raining.

4. 结果状语从句(so…that, such…that, so that, such as to, such that, so ,that, etc)

He ran so fast that I couldn’t catch him at all.

5. 目的状语从句（so that, in order that, lest, for fear that, in case, etc）

We wote the notice in several languages so that foreign tourists could also understand it.

6.条件状语从句（if, unless, in case(that), provided(that), suppose(that),as long as, etc.）

Unless he studies hard, he will never pass the examination.

7.让步状语从句(though, although, even if/though, while, as, granting/granted that,

admitting(that), no matter…, whatever, however, whether, etc.)

Admitting that he is clever, I don’t think he will be a top student, as he pays no attention to his lessons.

注意：as引导让步状语从句一般需要倒装

Poor though he is, his life is happy.

Child as/though he was, he knew what was the right thing to do.

Try as I will ，I cannot raise my voice.

Much as he likes her, he will not marry her.(虽然，尽管)

8.方式状语从句（（just）as, as if/though, etc.）

Do in Rome as the Romans do.

9.比较状语从句（as…as, not so…as, than, according as, the…the…, etc.）

The larger your vocabulary is, the faster you can read.

Ningbo generally receives less snow than Dalian does.