Grammar: Nonfinite Verbs & Infinitive (2) (语法：非谓语动词 & 动词不定式 (2))
4. 不定式作定语：
1) 修饰名词或代词，放在名词或代词的后面。这时被修饰的名词与不定式之间有主谓关系。
I have a lot of things to do.
There are so many books on education, so it is hard for me to decide
which book to buy.
Find yourself a chair to sit on.
I cannot find any weapon to use.
2) 一些表示企图、努力、打算、倾向、目的、能力等意义的名词和要求不定式作其宾语的动词的相应名词，其后要求不定式作其定
语，如： ability, attempt, effort, failure, intent…等。
When certain parts of the brain were damaged, men lost the ability todo certain things.
当大脑的某些部位损伤，人就会失去做某些事情的能力。
His failure to be selected as the delegate depressed us.
他没有被选作代表令我们沮丧。
5. 不定式作状语：作状语的不定式要与其逻辑主语在意义和数上保持一致 。
1) 表示目的
You need a special material to stick the two things together.
要把这两样东西粘在一起需要特别材料。
Animals must fight each other to stay alive.
2) 表示结果
He must earn money enough to support himself.
I am too sleepy to stay awake.
3) 表示原因
I am sorry to trouble you.
It’s very kind of you to say so.
6. 不定式作宾语补足语：下列这些动词往往要求宾语有补足语advise, allow, ask, enable, beg, cause, encourage, expect, force, get,
invite, persuade, pretend, teach, want…
Did you intend us to use this new method?
The teacher encourages us to use correct sentences.
His specialized training enables him to complete the task.
他的特别训练使他能够完成这项任务。
* 感官动词和某些使意动词的宾补可省略 to (help后可带to也可不带to )
I often heard him say that his family was very happy.
We must have a person clean the room.
I saw her cry in the street yesterday.
7. 不定式的一般式、完成式、进行式和完成进行式：
1) 不定式表示的动作和谓语表示的动作同时或几乎同时发生时，不定式用一般式。
Millions of people are waiting to welcome him.
A few years later he returned to find that his hometown had greatly changed.
2) 强调不定式表示的动作在谓语发生动作时正在发生，这时不定式用进行式。
When he came in I happened to be washing my feet.
He seems to be recovering.
3) 不定式表示的动作发生在谓语表示的动作之前，不定式用完成式。
She seems to have read the book before.
I feel relaxed to have finished a long journey.
4) 不定式表示的动作发生在谓语表示的动作之前，而且一直在进行，这时不定式用完成进行式。
We are happy to have been working with you for such a long time.
8. 动词不定式的被动形式：当动词不定式的逻辑主语是动作的承受者时，此不定式用被动语态。
Most of the dust seems to have been blown away.
“Do you have anything to be declared?”
有什么要申报的吗？
The next thing to be done is to pick up the baggage.