动词不定式
一. 定义：
动词不定式是非谓语动词的一种，它没有人称和数的变化，在句子中不能独立作谓语，但它仍保持动词的特点，既可以有自己的宾语和状语。

同时动词不定式又具有名词、形容词、副词的特征，在句中可以作主语、表语、宾语、宾语补足语、定语和状语。

二. 动词不定式的构成：to+动词原形
三. 动词不定式作宾语
动词不定式作宾语的注意事项（6点）
1.可以接带to的动词不定式作宾语的动词主要有：要求选择同意(ask, choose, agree)，期望决定学习(expect, hope, decide, learn)，宁可假装知道(prefer, pretend, know)，希望想要愿意(wish, want, would like / love)。

如：
1)We decided to talk to some students about why they go there.
2)He prefers to eat white bread and rice.
3)Id love to visit Mexico.
2.动词decide, know, learn, show, teach, tell...，介词结构on...可用疑问词带to 的不定式短语作宾语，但why后面的不定式不带to。

如：
1)Could you please tell me where to park my car?
2)It gives advice on what to do in lots of different situations.
3.动词feel, find, make, think等后面，可以用it作形式宾语代替真正的宾语——动词不定式，句子结构是...feel / find / make / ... it + adj. / n. + to do...。

如：
I find it difficult to remember everything.
4.既可接动词不定式又可接v_ing形式作宾语，意思差别不太大的动词有begin, start, like, love等。

一般说来，动词不定式表一次、数次的具体动作、将来动作或动作的全过程，v_ing形式表习惯性的连续动作。

但是这种区别并不很严格，特别是美国英语，即使是习惯性的动作也可以用动词不定式。

如：
1) Then I started to watch Tv.
2) I am beginning to understand my parents.
begin用了进行时态，后面只接不定式作宾语，表示事情刚开始，还要继续下去。

3) I like to eat vegetables.
感知动词like, love, know等一般不用进行时态。

5.后接动词不定式或v_ing形式作宾语，意思差别较大的动词有forget, remember等。

后接不定式作宾语，表动作尚未发生；后接v_ing形式作宾语，表动作已经发生。

stop to do 停下来做另外一件事，to do是目的状语；stop doing停止做、不做当前这件事，doing是宾语。

try to do尽力做，try doing试试看；go on to do接着做另外的事，go on doing 继续做原来的事。

如：
1)When I left home, I forgot to bring it with me.
2)I stopped using them last year.
6. 不定式作宾语时，如带有宾语补足语，则要把不定式放到后面，用it作形式宾语，构成“主语+动词+it+宾补（形容词、名词）+不定式”结构。

如：He found it very difficult to get to sleep. 他发现很难入睡。

( ) 1. I often see Tom____on the playground. When I passed the playground yesterday, I saw him_____.
A. play; playing
B. to play; play
C. playing; to play C. playing; play
( ) 2. — What does the sign on the bottle mean?
—It means “”.
A. This side up
B. Dangerous
C. Recyclable
D. No Parking
( ) 3. When the player finished running, he was out of ______. .
A. breather
B. breathing
C. breath
D. the breath
( ) 4. — How about going hiking this weekend?
— Sorry, I prefer rather than .
A. to stay at home; go out
B. to go out; stay at home
C. staying at home; go out
D. going out; stay at home
( ) 5. —We really shouldn’t use plastic bags any more when shopping.
—It’s important to protect our environment.
A. So does it.
B. With pleasure.
C. That’s OK.
D. So it is.
( ) 6. —
— To the supermarket with Wang Fan.
A. Where have you gone?
B. Where did you go to the supermarket?
C. Where have you been?
D. W here’s Wang Fang?
( ) 7. I afraid of the dark, but now I don’t.
A. use to
B. used to
C. use to be
D. used to be
( ) 8. The earth is years old.
A. four thousands six hundreds
B. four thousand six hundred
C. four thousand and six hundred million
D. four thousand six hundred millions ( ) 9. They have made so great progress .
A. three years ago
B. for three years
C. in the past three years
D. before three years
( ) 10. — Has Li Hong gone to the library?
— Pardon?
— I asked the library.
A. if Li Hong had gone to
B. if had Li Hong gone to
C. Li Hong had gone to
D. has Li Hong gone to
( ) 11. — Oh, Miss Wei. Your skirt looks nice. Is it new?
— No, I it since three years ago.
A. had
B. bought
C. have had
D. have bought
( ) 12. — Must they clean and tidy the classroom now?
— No, they . It after school in the afternoon.
A. mustn’t; must clean
B. needn’t; must clean
C. mustn’t; need be cleaned
;D. don’t have to; can be cleaned
( ) 13. —It’s one o’clock now. I must go.
—It’s raining outside. Don’t leave it stops.
A. when
B. since
C. while
D. until
( ) 14. your help, we can finish the task in time.
A. Thanks to
B. Thanks for
C. Because
D. Thank
( ) 15. We should plant more trees on sides of the street.
A. either
B. both
C. all
D. each。