非謂語動詞全面解析及練習(xí)——動詞不定式

　　在句中充當(dāng)除謂語以外的句子成分的動詞形式叫做非謂語動詞。非謂語動詞分為三種形式：不定式、動名詞和分詞(分詞包括現(xiàn)在分詞和過去分詞)

　　一、不定式

　　(一)不定式的作用

　　1、作主語 不定式作主語時，謂語用單數(shù)。往往用it 作形式主語，把不定式放在謂語后面。如：

　　It took us two hours to finish the job.

　　It is impossible for us to get there on time.

　　It is very kind of you to help us.

　　注意：(1)其他系動詞如look, appear等也可用于此句型。

　　(2)當(dāng)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。試比較：

　　It is to negate my own idea to believe him.(錯)

　　To believe him is to negate my own idea .(對)

　　(3)It is+ adj. of / for sb. to do sth. 結(jié)構(gòu)中，當(dāng)不定式的邏輯主語和前面的形容詞可以構(gòu)成系表結(jié)構(gòu)時，用of, 否則用 for.

　　2、作賓語

　　動詞+不定式。如：

　　He managed to escape from the fire.

　　I find it hard to get along with him.(it 作形式賓語)

　　注：下列動詞通常用不定式作賓語：want, try, hope, wish, need, forget, know, promise, refuse, help, decide, begin, start, learn, agree, choose, get等

　　動詞+疑問詞+to , “特殊疑問句+不定式”相當(dāng)于名詞，作賓語。如：

　　I don’t know what to do next/ how to do it next.

　　I can’t decide when to go there.

　　注意：不定式短語作賓語時，如果還帶有賓語補足語，往往把不定式短語放在賓語補足語之后，用it 作形式賓語。如：

　　I find it necessary to learn a foreign language.

　　3、作賓語補足語

　　動詞+賓語+不定式(to do )。如：

　　He warned me to be careful.

　　I want you to speak to Tom.

　　What makes you think so?(不帶to的不定式)

　　注：可以用動詞不定式做賓補的動詞有：ask, tell, order ,want ,get, would like, like, advise, invite, allow, help, wish,warn, expect, prefer, encourage

　　表見解、看法的動詞結(jié)構(gòu)可為：動詞+賓語+ to be 的不定式結(jié)構(gòu)。如：

　　We consider Tom to be one of the best students in our class.

　　The book is believed to be useful.(被動語態(tài))

　　(3) There +不定式。如：

　　We didn’t expect there to be so many people there.我們沒料到會有那么多人在那里。

　　注意：(1)有些動詞需用 as 短語作補語，像regard, think, believe, take, consider。如：

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

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

　　(2)在動詞feel (一感)，hear, listen to(二聽)，have, let, make(三讓)，notice, see, watch, observe, look at(五看)(即：吾看三室兩廳一感覺)等后面的補足語中，不定式不帶to，但變?yōu)楸粍诱Z態(tài)后，必須帶to。如：

　　They saw the boy fall off the tree. The boy was seen to fall off the tree.

　　(3)help后面作賓語補足語的不定式可以帶to,也可以不帶to.

　　I often help him (to)clean the room.

　　I helped him (to) find his things.

　　4、作定語

　　不定式作定語，修飾名詞或代詞，不定式和它所修飾的名詞之間有邏輯上的主謂關(guān)系、動狀關(guān)系、同位關(guān)系或動賓關(guān)系。不定式通常要放在這些被修飾的詞后。如：

　　I have a lot of work to do.(動賓關(guān)系)

　　He is looking for a room to live in.(動狀關(guān)系)

　　He is the first person to think of the idea.(主謂關(guān)系)

　　He has got a chance to go abroad.(同位關(guān)系)

　　注意：1.不定式的邏輯主語是句子的主語時，不定式用主動形式表被動。如：

　　Do you have anything else to say?

　　2.如果作定語的不定式是一個短語，則要保留不定時短語中的副詞或介詞。如：

　　I need a pen to write with . (I will wirte with the pen ) (我需要一直鋼筆寫字)

　　I have a little baby to look after .(I must look after the little baby ) (我有一個嬰兒要照看)

　　5、作狀語，表示目的、結(jié)果、原因等，有時還有一些固定搭配的不定式短語，如in order to , so as to, so…as to, such …as to, ….enough to, too…to等。

　　做目的狀語，to, only to (僅僅為了), in order to, so as to, so(such)….as to…(如此···以便···)如：

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

　　He came to the school to see his son.

　　作結(jié)果狀語，表事先沒有預(yù)料到的，要放在句子后面。如：

　　He hurried to the post office only to find it was closed.

　　He searched the room only to find nothing.

　　做原因狀語。如：

　　We were very excited to hear the news.

　　I’m glad to see you.

　　做條件狀語。如：

　　To turn to the left , you could find a post office.

　　6、作表語

　　不定式可放在be動詞后面，構(gòu)成表語。如：

　　The question is how to put it into practice.

　　My question is when to leave.

　　His dream is to be a doctor.

　　Her work is to look after the babies.

　　注意：1.不定式在句中作表語時，對應(yīng)的謂語動詞用單數(shù)。

　　2.當(dāng)助于是不定式時，表語不能用Ving形式，可用不定式。

　　如：To see is to believe. (眼見為實)

　　7、獨立結(jié)構(gòu)。如：

　　To tell you the truth, I don’t agree with you.

　　To make matters worse, it began to rain.

　　(二)不定式的時態(tài)和語態(tài)

　　1、不定式的時態(tài)

　　現(xiàn)在時：有時與謂語動詞表示的動作同時發(fā)生，有時發(fā)生在謂語動詞的動作之后。如：

　　He seems to know this. I hope to see you again.

　　完成時：表示的動作發(fā)生在謂語動詞表示的動作之前。如：

　　I’m sorry to have given you so much trouble.

　　He seems to have caught a cold.

　　進行時：表示動作正在進行，與謂語動詞表示的動作同時發(fā)生。如：

　　He seems to be eating something.

　　完成進行時：表示動作從過去某個時間開始，一直延續(xù)到現(xiàn)在，并有可能持續(xù)下去。如：

　　She is known to have been working on the problem for many years.

　　2、不定式的語態(tài)

　　當(dāng)不定式的邏輯主語是其動作的承受者時，就用被動式。如：

　　He was seen to enter the hall. He asked to be sent to work in Tibet.

　　(三)省to 的動詞不定式

　　1、情態(tài)動詞(除ought 外，ought to)

　　2、Would rather, had better.

　　3、感官動詞 see, watch, look at, notice, observe, hear, listen to, smell, feel 等后作賓補，省略 to.

　　注意：在被動語態(tài)中 to 不能省略掉。如：

　　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、使役動詞 let, have, make.

　　5、由 and, or 和 than 連接的兩個不定式，第二個 to 可以省去。如：He wants to move to France and marry the girl.

　　Help 可帶 to ,也可不帶to, help sb. (to) do sth.

　　Why…/Why not…

　　6、But 和 except 前是動詞 do 時，后面出現(xiàn)的動詞用不帶 to 的動詞不定式。試比較： He wants to do nothing but go out.

　　He wants to believe anything but to take the medicine.

　　7、通常在discover, imagine, suppose, think, understand 等詞后，可以省去to be .如：

　　He is supposed (to be) nice. 他應(yīng)該是個好人。

　　——I usually go there by train.

　　——Why not ______ by boat for a change?

　　A to try going B trying to go C to try and go D try going

　　Paul doesn’t have to be made ______ . He always works hard.

　　A learn B to learn C learned D learning

　　(四)、 動詞不定式的否定式。如：Tell him not to shut the window. She pretended not to see me when I passed by.

　　Mrs. Smith warned her daughter ______ after drinking.

　　A never to drive B to never drive C never driving D never drive

　　The boy wanted to ride his bicycle in the street, but his mother told him ______.

　　A not to B not to do C not do it D do not do

　　The patient was warned ______ food before the operation.

　　A to eat no B eating not C not to eat D not eating