动词不定式作宾语且过长时常请it作形式宾语，而让真的的宾语不定式断后。比如：
The man downstairs2 found3 it hard to fall asleep4.
2. 小品词to 的回避与复出
很多动词如teach，ask （要；让），tell，beg 等后常有带to的动词不定式作宾补；但let，have，make （让；使），feel，hear 等后作宾补的不定式结构，to 要回避。但在被动语态里to须重出江湖；help 后作宾补的不定式可加to，也可省略to.比如：
The policeman made5 the young woman move her car.
The young woman was6 made to move her car by the policeman.
[提示] 对不定式进行否定可在其前加not.如：let sb not do sth； tell sb not to do sth. 把直接引语为祈使句的句子变为间接引语，直接引语一般转换成不定式作宾补。比如：
The policeman said7. Dont play football in the street，children！
The policeman asked the children not to play football in the street.
3. 回答缘由，作目的状语
不定式（短语）常跟在come， go， run， hurry 等动词后作目的状语；或以in order8 to +动词原形、so as1 to +动词原形等形式出现，或回答what . . . for？ / why . . . ？问句。比如：
-Hi， Peter！ Why are you in such9 a hurry？
-To catch the 7：30 train.
[提示] 有时目的状语可置于句首，意为为了，等于in order to.比如：
To catch the bus， you must get up early.
在sTOP后的动词不定式其实是作目的状语，意为停下来做另一件事。比如：
Lets sTOP to have a meal10. I know a good restaurant near here.
4. 作状语，简化相应的复合句
作结果状语的不定式常以enough to . . . ，only to . . . ， too . . . to . . . 等形式登场，并能简化成so . . . that . . . 句式。比如：
Liu Mei was so lucky11 that she received13 many books from Project14 Hope15.
Liu Mei was lucky enough to receive12 many books from Project Hope.
5. 作后置定语
作定语时，不定式（短语）常置于被修饰的名词、不定代词等之后。比如：
Now China is the third country to send its astronauts16 into space after Russia17 and the US.
[提示]假如不定式（短语）是不及物动词，其后应有必要的介词/副词。比如：
I found a nice place for him to live in.
6. 不定式be to do sth可表以后
be to do sth 表以后，意为将要做某事。比如：
Our train is to leave at eight.
7. 年代弄潮儿疑问词+不定式
疑问词+不定式结构中的疑问词包含疑问代词which， who （m）， what 和疑问副词how， when， where 等，并常简化相应的从句，但当主句与从句的主语不同时，不定式常用被动形式。比如：
The little girl wanted to know when her father could18 take her to Pairs.
The little girl wanted to know when to be taken to Pairs by her father.
