不定词概述

• 所谓“不定词短语”，就是to 加上原形动词所形成的短语。
• 最合理的解释就是把它视为助动词的变化。

不定词和助动词的共同点。

• I am glad to know you.
• I am glad because I can know you.
• to know 就是 able to know 也就是can know 的变化

后面都加原形动词

• I will go.
• I want to go.

都有“不确定”的语气

• He is right.
• He may be right.
• He seems to be right.

都要用完成式来表达相对的过去时间

• 助动词和不定词本身都无法完整表达过去时间。只好用完成式表示过去
• It must have rained last night
• It seems to have rained last night.

所有重要的语气助动词都可以改写为不定词

• must -> have to
• should -> ought to
• will/would -> be going to
• can/could -> be able to
• may/might -> be likely to

其实不定词与助动词是同一种东西的相互转换。

传统语法所称的动状词

1. 现在分词：adj类
2. 过去分词：adj类
3. 动名词：n类
4. 不定词：不确定什么词类，可以是n，adj，adv

E.g. avoid.

• I avoid makeing the same mistake twice.
• to make 是will make 的省略,既然是避免，后面又will make、意思就变得不清楚了。
• I avoid something. ->
• I will make the same mistake twice.

E.g. plan

• They plan to marry next month.
• to marry -> they will marry.

E.g. hate

• I hate to say this, but I think you're mistaken.
• to say -> I have to say -> must say.

E.g. try

• I always try to be on time.
• to be on time -> I can be on time.

E.g. remember

• Please remember to give me a wake-up call at 6:00 tomorrow.

• -> Please remember you must give me a cll(will give)

• I remember calling her at 6:00 last night.

• -> I remember that I called her last night.

• 这时是确定的事实语气，没有助动词存在，既然不能用不定词那么只好用动名词。

E.g. stop

• The speaker stopped talking at the second bell.

• talking -> he was talking.

• 用talking 来表示动作的持续性

• The speaker stopped a second to drink some water.

• to drink -> he could drink 的变化

• The speaker stopped a second so that he could drink some water.

使役动词与原形动词

• 了解不定词是什么，就能了解使役动词后面为什么会加动词原形。
• The little girl asked her monther to come to the PTA meeting.
• -> The little girl asked if her monther would come to PTA meeting.
• ask 普通动词
• The teacher made the little girl stay behind.
• made 使役动词
• 后者由强制性，别无选择。
• The teacher asked the little girl to stay behind.

1. Not wishing on attend the dance, Marie made believe that she had a fever.
2. He is saied by his friends to be gentle and gracious.
3. To explain any aspect of animal vehavior, the biologist must first determine the laws influencing animal behavior.
4. "I'll help you whenever you need me.""good, I'd like you to help me tomorrow."
5. "Where did he go?""He went to another store to but slacks."
6. To make silk, the silkworm makes a liquid in its body and then squeezes it out through special holes.
7. I am a peaceful person. Don't make me use violence.
8. Americans are used to having back and eggs for breakfast every day.
9. The bus driver told the man not to allow his naughty son to hang out the window.
10. To get an eduction, one must work hard.
11. The purpose of the investigation is to ascertain the suspect 's degree of involvement is crime.
12. The witness went on the witness stand to be questioned by the prosecution.
13. You can playback the answering machine.She could have called.
14. You should avoid using vague words in your composition.
15. He is waiting at the restaurant for a free table because he forget to make a reservation in advance.
16. We can go out now. It stopped raining quite a while ago.
17. To be able to write an academic paper, you must do a lot of library research.
18. He always has his shoes shined at the railway station.
19. Don't sit up too late, for night is a time to rest.
20. He was made to read the Bible every night before going to bed.