李 萍

動詞不定式的基本形式是“to+動詞原形”,有時可不加to。下面就不定式使用時需注意的幾個方面加以說明。

1. 動詞不定式作主語。

不定式作主語,不定式結(jié)構(gòu)所表示的動作是誰做的,即不定式的邏輯主語,通常在特定的上下文中能看出,也可以通過帶“for+名詞短語”辨出。在某些形容詞(如careless, clever, considerate, foolish, good, impolite, kind, naughty, nice, silly, stupid等)作表語時,不定式后可以加of來引出其邏輯主語。

It is very important for us to master a skill in modern times.

Its very kind of you to lend me a hand when I am in trouble.

It is not difficult for those who study maths well to pass the exam.

It is stupid of him to do such a silly thing.

間或也可用for + there to be 表示(而且there后面的不定式只能是to be)。

Its a great pity for there to be much trouble in the company.

2. 不定式作賓語有兩種形式:

A)只能接不定式作賓語的動詞主要有:afford, agree, aim, appear, arrange, ask, believe, care, claim, decide, demand, desire, determine, expect, fail, hesitate, hope, intend, learn, long, manage, mean(想要), offer(表示愿意做……), pretend, promise, refuse, seek(試圖), undertake, wish(想要)等。

He pretended to be sleeping when I came in.

We managed to complete the task in time though we met with a lot of trouble.

B)動詞+疑問代(副)詞+不定式

這類動詞常見的有:advise, decide, discuss, find out, forget, know, learn, regard, remember, see, settle, teach, tell, think(=consider), understand, wonder等。這些疑問代(副)詞有what, when, where, which, how, whether等,但不包括why。如:

On hearing the news, he didnt know whether to laugh or to cry.

When to hold the meeting has not decided.

The most important problem is how to get so much money.

You can decide whether to go forward or stay here.

注意:介詞后一般不直接接不定式,但可以接“疑問詞+不定式短語”作賓語。如:

Mary gave some advice on how to learn English.

3.有些動詞既可接不定式又可接動名詞作賓語,但意義有別?，F(xiàn)將常見的動詞辨別如下:

A)既能跟動詞不定式也能跟動名詞形式作賓語的動詞有:like, love, begin, start, hate。

Tomorrow I start to work(working).

Do you like to play(playing) football?

注意:動名詞表示一般習(xí)慣性動作,而不定式則表示具體的動作。

B)在下面情況下一般用動詞不定式作賓語:

①would like/love后,表示特定動作時。

Would you like to attend his wedding?

②當(dāng)謂語已經(jīng)用了進行時態(tài)時。

Its beginning to rain.

③在begin后非限定動詞由某些狀態(tài)動詞構(gòu)成時。

We began to think of this question.

C)動名詞和動詞不定式作賓語時意思不同的動詞。

①need,want跟動名詞形式作賓語時表示被動意義,跟動詞不定式作賓語時表示主動意義。試比較下面的句子:

These trees need watering(to be watered).

We need to take care of the children living with the old man.

Your hair needs cutting(to be cut).

I want to see him.

②remember, forget, stop, go on等動詞后跟動名詞作賓語時,表示動名詞的動作發(fā)生在謂語動詞動作之前;跟動詞不定式作賓語時,表示動詞不定式的動作發(fā)生在謂語動詞動作之后。試比較下面的句子:

I remember telling you about it once.

這事我記得曾和你談過一次。

You must remember to write to us when you get there. 你到那里時,千萬別忘了給我們寫信。

Go on reading the text. 繼續(xù)讀課文。

After he finished the composition, he went on to do his homework.他寫完作文后接著做作業(yè)。

She stopped speaking. 她停止講話。

He stopped to speak to Martin. 他停下來和馬丁說話。(動詞不定式to speak在句中作狀語)

③try和mean跟動名詞和動詞不定式作賓語時,在意思上差別很大。

a. try跟動名詞作賓語時是“試著做某事”的意思;而跟動詞不定式作賓語時是“設(shè)法做某事”的意思。試比較下面句子:

She tried writing a composition.

她試著寫作文。

She tried to get you on the phone.

她設(shè)法打電話找你。

b. mean跟動名詞作賓語時是“意思是”、“意味著”的意思;而跟動詞不定式時是“企圖、打算”的意思。試比較下面句子:

This means wasting much money.

這意味著浪費很多錢。

I meant to call on you. But I was so busy.

我是想來看望你的,但我太忙了。

4. 有些“be+形容詞”結(jié)構(gòu)需要用不定式作狀語。

在這個結(jié)構(gòu)中,不定式部分?？醋魇菭钫Z,這些形容詞通常有:able, afraid, anxious, determined, eager, free, glad, pleased, ready, sorry, sure, willing等。

I am sorry to hear that you were late for the train.

We are determined to take part in the sports meet to be held next week.

5. 不定式符號需省略或不省略的特征。

A)在hear, see, watch, notice, make, let, feel等動詞后作賓語的不定式要省略to。但在被動語態(tài)中,省去的to需要補出。help后動詞可接to也可不接。

They made the man work all the night.

The man was made to work all the night.

Suddenly I noticed a stranger in black enter the hall.

B)在why not, had better后不定式省去to。

Why not ask for advice from your parents?

Youd better have a rest and prepare for the next driving test.

C)當(dāng)一個不定式結(jié)構(gòu)被省略時,to需要保留下來,以代表被省去的不定式結(jié)構(gòu)。

——Would you like to go with me?

——Id like to, but I have to take care of my sister.

6. 區(qū)分作感官動詞賓補的現(xiàn)在分詞和不定式。

不定式作賓補表示動作已經(jīng)發(fā)生過,而用現(xiàn)在分詞作賓補則表示動作與謂語所表示的動作同時進行。

I heard them singing a song when I passed his room just now. (表示sing和pass同時進行)

I saw him cross the river an hour ago. (表示動作已經(jīng)結(jié)束)

7. 慎用句尾的不定式。

及物動詞的不定式需加賓語。但用于句尾的不定式有時雖然是及物的,然而后面并不帶賓語。這是由于在句首或句中已有其邏輯賓語,這時不定式后就不應(yīng)該再跟賓語了(接雙賓語的動詞除外)。若不定式是不及物動詞時,需加上適當(dāng)?shù)慕樵~或副詞。

The work is too much for a child like him to do. (do之后不能再加it)

He is looking for a house to live in.