英語(yǔ)語(yǔ)法也是學(xué)習(xí)英語(yǔ)的一個(gè)難點(diǎn)，弄懂語(yǔ)法對(duì)看懂句子很有幫助。在語(yǔ)法中，動(dòng)詞不定式是指動(dòng)詞的一種不帶詞形變化從而不指示人稱、數(shù)量、時(shí)態(tài)的形式。它之所以被叫做不定式，是因?yàn)閯?dòng)詞不被限定，或者說(shuō)不被詞形變化所局限。下面我們一起來(lái)看下動(dòng)詞不定式的用法口訣順口溜，這樣記對(duì)你有好處。

英語(yǔ)動(dòng)詞不定式用法順口溜：

不定式有標(biāo)記，to與動(dòng)原連一起。

沒有人稱數(shù)變化，動(dòng)詞特點(diǎn)它具備。

主賓定狀表狀語(yǔ)，惟獨(dú)作謂不可以。

not加上不定式，否定結(jié)構(gòu)要牢記。

疑問(wèn)詞與不定式，構(gòu)成短語(yǔ)有意義。

仔細(xì)推敲多思考，準(zhǔn)確判斷有依據(jù)。

巧記接不定式的動(dòng)詞

三個(gè)希望兩答應(yīng)(Hope, wish, want, agree, promise)

兩個(gè)要求莫拒絕(Demand, ask, refuse )

設(shè)法學(xué)會(huì)做決定(Manage, learn, decide )

不要假裝在選擇(Pretend, choose )

動(dòng)詞不定式具體用法

1.不定式定義:由to+動(dòng)詞原形構(gòu)成.

不定式是一種非限定性動(dòng)詞.而非限定動(dòng)詞是指那些在句中不能單獨(dú)充當(dāng)謂語(yǔ)的動(dòng)詞,可分為不定式,動(dòng)名詞,現(xiàn)在分詞和過(guò)去分詞.

2.用途：

在句中不能作謂語(yǔ).它具有動(dòng)詞的性質(zhì),本身可以帶賓語(yǔ)和狀語(yǔ).

【動(dòng)詞不定式】

1.定義：動(dòng)詞 + 不定式

2.用途：

動(dòng)詞不定式在句中可以作句子任何成分.動(dòng)詞不定式的被動(dòng)形式除了一般形式外還有其完成式和進(jìn)行式.

[編輯本段][動(dòng)詞不定式的時(shí)態(tài)、語(yǔ)態(tài)]

動(dòng)詞不定式可以作以上各種成分,但它畢竟是動(dòng)詞,所以有動(dòng)詞的屬性

動(dòng)詞不定式及其短語(yǔ)還可以有自己的賓語(yǔ)、狀語(yǔ),雖然動(dòng)詞不定式在語(yǔ)法上沒有表面上的直接主語(yǔ),但它表達(dá)的意義是動(dòng)作,這一動(dòng)作一定由使動(dòng)者發(fā)出.這一使動(dòng)者我們稱之為 邏輯主語(yǔ),其形式如下：

主動(dòng)形式 被動(dòng)形式

一般式 (not) to make (not) to be made

完成式 (not) to have made (not) to have been made

進(jìn)行式 (not) to be making

完成進(jìn)行式 (not) to have been making

(1)語(yǔ)態(tài)

如果動(dòng)詞不定式的邏輯主語(yǔ)是這個(gè)不定式所表示的動(dòng)作的承受者,不定式一般要用被動(dòng)語(yǔ)態(tài)形式.如：

It's a great honour to be invited to Mary's birthday party.(不定式作主語(yǔ))

It was impossible for lost time to be made up.(不定式作主語(yǔ))

I wish to be sent to work in the country.(不定式作賓語(yǔ))

Can you tell me which is the car to be repaired?(不定式作定語(yǔ))

He went to the hospital to be examined.(不定式作狀語(yǔ))

在There be結(jié)構(gòu)中,修飾主語(yǔ)的不定式可用被動(dòng),也可用主動(dòng).如：There are still many things to t ake care of (to be taken care of).但有時(shí)兩種形式表達(dá)的意思不同,如：These is nothing to do now.( We have nothing to do now.) There is nothing to be done now.(We can do nothing now.)

(2)時(shí)態(tài)

1) 現(xiàn)在時(shí)：一般現(xiàn)在時(shí)表示的動(dòng)詞,有時(shí)與謂語(yǔ)動(dòng)詞表示的動(dòng)作同時(shí)發(fā)生,有時(shí)發(fā)生在謂語(yǔ)動(dòng)詞的動(dòng)作之后.

He seems to know this.

I hope to see you again.= I hope that I'll see you again.我希望再見到你.

2) 完成時(shí)：表示的動(dòng)作發(fā)生在謂語(yǔ)動(dòng)詞表示的動(dòng)作之前.

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

He seems to have caught a cold.

3) 進(jìn)行時(shí)：表示動(dòng)作正在進(jìn)行,與謂語(yǔ)動(dòng)詞表示的動(dòng)作同時(shí)發(fā)生.

He seems to be eating something.

4) 完成進(jìn)行時(shí)：

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

[編輯本段][疑問(wèn)詞+不定式結(jié)構(gòu)]

疑問(wèn)詞who,what,which,when,where,whether,how后可接不定式構(gòu)成不定式短語(yǔ),在句中作主語(yǔ)、賓語(yǔ)、表 語(yǔ)等.如：

①When to leave for London has not been decided yet.(不定式在句子中做主語(yǔ))

②Mr.Smith didn't know whether to leave or stay there.(不定式在句子中做賓語(yǔ))

③I asked Professor Xu how to learn English well.(不定式在句子中做間接賓語(yǔ))

④The question was where to get the medicine needed.(不定式在句子中表語(yǔ))

以上例句中疑問(wèn)詞+不定式部分,均可轉(zhuǎn)換為相應(yīng)的從句形式.如：①When we shall leave…③…how I

could learn…

經(jīng)常在這種結(jié)構(gòu)中使用的動(dòng)詞有：consider,decide,discover,explain,find out,forget,hear,know,lea rn,observe,understand,wonder等.

[編輯本段][動(dòng)詞不定式的語(yǔ)法功能]

一、作主語(yǔ)

動(dòng)詞不定式作主語(yǔ)時(shí),句子的謂語(yǔ)動(dòng)詞常用單數(shù),其位置有以下兩種：

(1)把不定式置于句首.如：

To get there by bike will take us half an hour.

(2)用it作形式主語(yǔ),把真正的主語(yǔ)不定式置于句后,常用于下列句式中.如：

①It+be+名詞+to do

It's our duty to take good care of the old.

②It takes sb+some time+to do

How long did it take you to finish the work?

③It+be+形容詞+for sb+to do

It is difficult for us to finish writing the compositionin a quarter of an hour.

④It+be+形容詞+of sb+to do

It is stupid of you to write down everything the teachersays.

⑤It seems(appears)+形容詞+to do