動詞不定式的用法

　　1 不定式作賓語

　　動詞+ 不定式

　　afford, aim, appear, agree, arrange, ask, be, decide, bother, care, choose, come, dare, demand, desire, determine, expect, elect, endeavor, hope, fail, happen, help, hesitate, learn, long, mean, manage, offer, ought, plan, prepare, pretend, promise, refuse, seem, tend, wait, wish, undertake

　　The driver failed to see the other car in time.　司機沒能及時看見另一輛車。

　　I happen to know the answer to your question.　我碰巧知道你那道問題的答案。

　　2) 動詞+不定式;動詞+賓語+不定式

　　ask, beg, choose, expect, hate, help intend like, love, need prefer, prepare, promise, want, wish

　　I like to keep everything tidy.　我喜歡每件東西都保持整潔。

　　I like you to keep everything tidy.　我喜歡你使每件東西都保持整潔。

　　I want to speak to Tom.　 我想和湯姆談話。

　　I want you to speak to Tom.　 我想讓你和湯姆談話。

　　3) 動詞+疑問詞+ to

　　decide, know, consider forget, learn, remember, show, understand, see, wonder, hear, find out, explain, tell

　　Please show us how to do that. 請演示給我們如何去做。

　　There are so many kinds of tape-recorders on sale that I can't make up my mind which to buy.有這么多的錄音機，我都拿不定主意買哪一種。

　　注意

　　疑問詞帶不定式在句中作成分時，謂語動詞用單數(shù)。如：The question is how to put it into practice. 問題是怎樣把它付諸實施。

　　2. 不定式作補語

　　1) 動詞+賓語+不定式(to do)

　　advise, allow, appoint, believe, cause, challenge, command, compel, consider, declare, drive, enable, encourage, find, forbid, force, guess, hire, imagine, impel, induce, inform, instruct, invite, judge, know, like, order, permit, persuade, remind, report, request, require, select, send, state, suppose, tell, think, train, trust, understand, urge, warn

　　a. Father will not allow us to play on the street.　父親不讓我們在街上玩耍。

　　b. We believe him to be guilty. 我們相信他是有罪的。

　　Find 的特殊用法

　　Find 后可用分詞做賓補，或先加形式賓語，再加形容詞，最后加帶to 的動詞不定式。find后也可帶一個從句。此類動詞還有get，have。

　　I found him lying on the ground.

　　I found it important to learn.

　　I found that to learn English is important.

　　典型例題

　　The next morning she found the man ___ in bed，dead.

　　A. lying　 B. lie　 C. lay　 D. laying

　　答案：A. find的賓語后面，用分詞或分詞短語，起賓語補足語作用?，F(xiàn)在分詞表達主動，也表達正在進行，過去分詞表達被動。

　　2) to + be 的不定式結構，作補語的動詞。

　　acknowledge, believe, consider, think, declare(聲稱), discover, fancy(設想), feel, find,　guess, judge, imagine, know, prove, see(理解), show, suppose, take(以為), understand

　　We consider Tom to be one of the best students in our class. 我們認為湯姆是班上最好的學生之一。

　　典型例題

　　Charles Babbage is generally considered　___ the first computer.

　　A. to invent　B. inventing　 C. to have invented　 D. having invented

　　答案：A. 由consider to do sth. 排除B、D。. 此句只說明發(fā)明這一個事實，不定式后用原形即可。而C為現(xiàn)在完成時，發(fā)明為點動詞一般不用完成時，且此處也不強調對現(xiàn)在的影響，因此不選C。

　　3) to be +形容詞

　　seen, appear, be said, be supposed, be believed, be thought, be known, be reported, hope, wish, desire, want, plan, expect, mean

　　The book is believed to be uninteresting.　人們認為這本書沒什么意思。

　　4) there be+不定式

　　believe, expect, intend, like, love, mean, prefer, want, wish, understand

　　We didn't expect there to be so many people there. 我們沒料到會有那么多人在哪里。

　　注意

　　有些動詞需用as 短語做補語，如regard, think believe, take, consider.

　　We regard Tom as our best teacher.　我們認為湯姆是我們最好的老師。

　　Mary took him as her father .　瑪麗把他當作自己的父親。

　　1) It's easy (for me) to do that. 我做這事太容易了。

　　easy, difficult, hard, important, possible, impossible, comfortable, necessary, better;

　　the first, the next, the last, the best, too much, too little, not enough

　　It's so nice to hear your voice.　聽到你的聲音真高興。

　　It's necessary for you to lock the car when you do not use it. 當你不用車的時候，鎖車是有必要的。

　　2) It's very kind of you to help us. 他幫助我們，他真好。

　　kind, nice, stupid, rude, clever, foolish, thoughtful, thoughtless, brave, considerate(考慮周到的), silly, selfish(自私的)

　　It was silly of us to believe him.　我們真愚蠢，竟然相信了他。

　　It seemed selfish of him not to give them anything.　他不給他們任何東西，這顯得太自私了。

　　注意

　　1) 其他系動詞如，look，appear等也可用于此句型

　　2) 不定式作為句子成分時，動詞用單數(shù)形式。

　　3) 當不定式作主語的句子中又有一個不定式作表語時，不能用It is… to…的句型

　　(對)To see is to believe.　百聞不如一見。(錯)It is to believe to see.

　　It's for sb.和 It's of sb.

　　1) for sb. 常用于表示事物的特征特點，表示客觀形式的形容詞，如easy, hard, difficult,　 interesting, impossible等：

　　It's very hard for him to study two languages. 對他來說學兩門外語是很難的。

　　2) of sb的句型一般用表示人物的性格，品德，表示主觀感情或態(tài)度的形容詞，如good, kind, nice, clever, foolish, right。

　　It's very nice of you to help me. 你來幫助我，你真是太好了。

　　for 與of 的辨別方法

　　用介詞后面的代詞作主語，用介詞前邊的形容詞作表語，造個句子。如果道理上通順用of，不通則用for。如：You are nice.　(通順，所以應用of)。He is hard.　(人是困難的，不通，因此應用for。)

　　4. 不定式作表語

　　不定式可放在be動詞后面，形成表語。例如：

　　My work is to clean the room every day.

　　His dream is to be a doctor.

　　5. 不定式作定語

　　不定式做定語通常要放在被修飾的詞后。例如：

　　I have a lot of work to do.

　　So he made some candles to give light.