不定式

1、動詞不定式形式：（to）+do具有名詞、形容詞、副詞的特征；否定式：not+(to) do

2、不定式的句法功能：

（1）作主語：

To finish the work in ten minutes is very hard.

To lose your heart means failure.

動詞不定式短語作主語時，常用it作形式主語，真正的主語不定式置于句后，例如上面兩句可用如下形式：

It is very hard to finish the work in ten minutes.

It means failure to lose your heart.

常用句式有：

1、It+be+名詞+to do。

2、It takes sb.+some time+to do。

3、It+be+形容詞+of sb +to do。

4、It+be+形容詞+for sb.+to do。

常用careless,,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise,等表示贊揚或批評的形容詞，不定式前的sb.可作其邏輯主語。

（2）作表語：

Her job is to clean the hall.

He appears to have caught a cold.

（3）作賓語：

常與不定式做賓語連用的動詞有：want, hope, wish, offer, fail, plan, learn, pretend, refuse, manage, help, agree, promise, prefer, 如果不定式（賓語）后面有賓語補足語，則用it作形式賓語，真正的賓語（不定式）后置，放在賓語補足語后面，例如：

Marx found it important to study the situation in Russia. 動詞不定式也可充當介詞賓語，如： I have no choice but to stay here.He did nothing last Sunday but repair his bike.

動詞不定式前有時可與疑問詞連用，如： He gave us some advice on how to learn English.

（4）作賓語補足語： 在復合賓語中，動詞不定式可充當賓語補足語，如下動詞常跟這種復合賓語：want, wish, ask, tell, order, beg, permit, help, advise, persuade, allow, prepare, cause, force, call on, wait for, invite.

此外，介詞有時也與這種復合賓語連用，如： With a lot of work to do, he didn"t go to the cinema．有些動詞如make, let, see, watch, hear, feel, have等與不帶有to的不定式連用，但改為被動語態時，不定式要加to, 如： I saw him cross the road. /He was seen to cross the road.

（5）作定語：

動詞不定式作定語，放在所修飾的名詞或代詞后。與所修飾名詞有如下關系：

①動賓關系：

I have a meeting to attend.注意：不定式為不及物動詞時，所修飾的名詞如果是地點、工具等，應有必要的介詞，如：He found a good house to live in.The child has nothing to worry about.

如果不定式修飾time, place, way，可以省略介詞：He has no place to live. This is the best way to work out this problem.

如果不定式所修飾名詞是不定式動作承受者，不定式可用主動式也可用被動式：Have you got anything to send? Have you got anything to be sent?

②說明所修飾名詞的內容：

We have made a plan to finish the work.

③被修飾名詞是不定式邏輯主語：

He is the first to get here.

3、難點解析

（1）接不定式或動名詞在意思上有區別的動詞：

fmean to do想要(做某事)propose to do打算(做某事)

mean doing意味(做某事)propose doing建議(做某事)

forget to do忘記(要做的事)remr to do記得(要做某事)

forget doing忘記(已做的事)remr doing記得(已做過的事)

regret to do(對將要做的事)遺憾go on to do繼而(做另一件事)

regret doing(對已做過的事)后悔go on doing繼續(做原來的事)

fstop to do停下來去做另一件事

stop doing停止正在做的事

（2）下列動詞短語中的to是介詞，后面應接動名詞或名詞：

resort to，react to，contribute to，look forward to，be accustomed to，be committed to.be exposed to，be subjected to，be devoted to，be dedicated to，be opposed to，be reconciled to，be contrary to