動詞不定式

 　　1 不定式作賓語

　　1) 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.有這麼多的答錄機，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。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 後可用分詞做賓補，或先加形式賓語，再加形容詞，最後加帶to 的動詞不定式。find後也可帶一個從句。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的賓語後面，用分詞或分詞短語，起賓語補足語作用。現在分詞表達主動，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。. 此句只說明發明這一個事實，不定式後用原形即可。而C為現在完成時，發明為點動詞一般不用完成時，且此處也不強調對現在的影響，因此不選C。

　　3) to be +形容詞

　　seem, 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麼意思。

　　4) there be+不定式

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

　　We didn't expect there to be so many people there. 我們沒料到會有那麼多人在哪裡。

　　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。

　　3. 不定式作主語

　　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等也可用於此句型

　　2) 不定式作為句子成分時，動詞用單數形式。

　　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. 常用於表示事物的特徵特點，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

　　用介詞後面的代詞作主語，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動詞後面，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後。例如：

　　I have a lot of work to do.

　　So he made some candles to give light.

　　6. 不定式作狀語

　　1) 目的狀語

　　To… only to (僅僅為了), in order to, so as to, so(such)… as to… (如此……以便……)

　　He ran so fast as to catch the first bus.　他飛快地跑以便趕上第一班車。

　　I come here only to say good-bye to you.　我來僅僅是向你告別。

　　2) 作結果狀語，表事先沒有預料到的，要放在句子後面。

　　What have I said to make you angry.

　　He searched the room only to find nothing.

　　3) 表原因

　　I'm glad to see you.

　　典型例題

　　The chair looks rather hard, but in fact it is very comfortable to ___.

　　A. sit　 B. sit on　 C. be seat　 D. be sat on

　　答案：B.　如果不定式為不及物動詞，其後應有必要的介詞。當動詞與介詞連用時，常位於"形容詞+動詞不定式"結構的末尾。

　　用作介詞的to

　　to 有兩種用法：一為不定式+動詞原形; 一為介詞+名詞/動名詞, to 在下面的用法中是第二種，即to+ 名詞/動名詞：admit to承認，confess to承認，be accustomed to 習慣於，be used to 習慣於，stick to 堅持，turn to開始，著手於，devote oneself to 獻身於，be devoted to 致力於， look forward to 盼望，pay attention to

　　注意

　　省to 的動詞不定式

　　1) 情態動詞 ( 除ought 外，ought to)：

　　2) 使役動詞 let, have, make：

　　3) 感官動詞 see, watch, look at, notice , observe, hear, listen to, smell, feel, find 等後作賓補，省略to。

　　注意

　　在被動語態中則to 不能省掉。

　　I saw him dance. =He was seen to dance.

　　The boss made them work the whole night.=They were made to work the whole night.

　　4) would rather，had better：

　　5) Why… / why not…：

　　6) help 可帶to，也可不帶to, help sb (to) do sth：

　　7) but和except：but前是動詞do時，後面出現的動詞用不帶to的動詞不定式。

　　8) 由and, or和than連接的兩個不定式，第二個to 可以省去：

　　9) 通常在discover, imagine, suppose, think, understand等詞後，可以省去to be：He is supposed (to be) nice.　他應該是個好人。舉例：He wants to move to France and marry the girl. He wants to do nothing but go out. 比較：He wants to do nothing but go out. He wants to believe anything but to take the medicine.