动词不定式练习题及讲解说课讲解

动词不定式练习题及

讲解

动词不定式用法要点讲解

一、作主语

动词不定式作主语时，句子的谓语动词常用单数，其位置有以下两种：

(1)把不定式置于句首。如：

To get there by bike will take us half an hour.

(2)用it作形式主语，把真正的主语不定式置于句后，常用于下列句式中。如：

①It＋be＋名词＋to do

It's our duty to take good care of the old.

②It takes sb+some time+to do

How long did it take you to finish the work?

③It＋be＋形容词＋for sb＋to do

It is difficult for us to finish writing the composition a quarter of an hour.

④It＋be＋形容词＋of sb＋to do

It is stupid of you to write down everything the teacher says.

⑤It seems(appears)＋形容词＋to do

It seemed impossible to save money.

二、作宾语

⒈不定式作宾语

①以下动词后，只能跟不定式作宾语。如：

agree,ask,aim,arrange,choose,decide,demand,expect,fail ,help,hope,lean,long manage,offer,plan,prepare,pretend,promise,refuse,wish等，这些词大部分可接

th at引导的从句。如：

When our visit to the farm was over, we expected to start back on foot. When our visit to the farm was over, we expected that we would start back on foot.

②当复合宾语中的宾语是不定式时，先用形式宾语it代替不定式，把不定式置于补语之后，即：主语＋动词＋it＋补语＋to do句式。

He feels it his duty to help the poor.

③介词but,except,besides+to do(do)

在这种句型中，如介词前有动词do，后面应接不带to的不定式；如无do，则接to 不定式，即带do不带to，带to不带do。如：

The enemy soldiers had no choice but to give in. ⒉部分动词后面，既可接动词不定式，也可接动名词作宾语，意义不变。如：begin,continue,start,hate,like,love,need,require,want等。

在need,require,want后接-ing形式，表示被动意义，也可接不定式，但要用被动形式，如：Your handwriting needs improving(tobe improved). hate,love,like接不定式表示特定的未来事件，接动名词表示目前正在进行的活动或一般的行为。

在下列情况下，一般要用不定式：

①hate,like,love前有would(should)时，如：I'd like to have a cup of coffee.

②当谓语动词begin,continue,start等是进行式时，如：Thestudents are starting to work on the difficult maths problem.

③begin,continue,start与know,understand等状态动词连用时，如：I soon began to understand what was happening.

3．advise,allow,encourage,forbid,permit等动词后接动名词作宾语，或带不定式作宾语补足语。如：

Our teachers don't permit our/us swimming in the lake.

Our teachers don't permit us to swim in the lake.

4．部分动词后接不定式或动名词时，意义差别较大，应根据句子语境选择使用。

①forget,remember,regret后接不定式，表示现在或未来的动作，接动名词表示动作已经发生。如：

We regret to tell you that all of you are not invited to attend the meeting. They regretted ordering these books from abroad.

②mean to do 打算做某事 ;mean doing 意味着……

③try to do 设法尽力做某事; try doing 试着做某事

④stop to do 停下一件事去做另一件事（不定式作目的状语）; stop doing 停止做某事

⑤can't help doing 禁不住…; can’t to do不能帮助干……

⑥go on to do 做不同的事或不同内容的事;

doing 继续不停地做某事，指同一动作的继续

⑦leave off to do 离开某地去干什么（目的状语）; leave doing停下某事

三、做表语

To be kind to the enemy is to be cruel to the people.

四、作定语

不定式在句中作定语，置于被修饰的名词或代词之后。如：

Have you anything to be taken to your sister?

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