before的用法,before和after用法详解

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before的用法,before和after用法详解(1)

一、It be some time before…

此句型关键有四种含义,分别阐述如下:

1.该句中主句为将来时态,before从句为一般现在时态;主句为一般过去时,从句通常也为过去的时态。

2.例如:

It will be some months before we graduate from school.(过几个月,我们就毕业了。)

Shall we see him again? (我们还能见到他吗?)

I think so. It won’t be long before he comes back to the hometown.(我想会的,过不了多久他又返回家乡。)

该句型中的时间长为long, a long time, years, months, weeks, days, hours, minutes等时间段。此句型容易与强调句型混淆,试比较:

It was two years before he came back from abroad.(过了两年他才从国外回来。)

It was two years later before he came back from abroad.(两年之后他才从国外回来。)

第一句为状语从句,it 表示时间;第二句为强调句型,强调的是时间状语two years later。

3.该句型的引申为“还没来得及……就……”。请看例句

Someone called me up in the middle of the night, but they hung up before I could answer the phone.(半夜里有人打电话,但是我还没来得及回答他就挂了。)

before的用法,before和after用法详解(2)

4.该句型还有一个引申含义为“……之后才……”,多与持续性时间、动作连用。例如:

Several weeks had gone by before I realized the painting was missing.(几周之后,我才意识到那幅画丢了。

二、“not…before”句型有时可换成“hardly…when…”或“scarcely…when”句型

例如:

They had not talked for half an hour before she entered. =They had hardly/scarcely talked for half an hour when she entered.

三、“not…before”句型同“not…until”句型意思相同,表示“直到……才,在……以前不……”(即在否定句中,until 和 till 可以和非延续性动词连用,这时 until 和 before 近义)

比较例句:

She stood there till/until he had passed out of sight.(不用before)他一直站在那儿,直到他消失。

The moon will not come out until/before the clouds disappear.云散了月亮才会出来。

One doesn’t know the value of health before/until he loses it.人们失去了健康后才知道健康的珍贵。

四、Before, after与behind

before表时间、顺序或排列时与after相对;表位置时与behind相对。例如:

I saw the headmaster the day before yesterday.我前天见到了校长(时间)。

Autumn comes before winter.秋去冬来(顺序)。

A comes before B in the alphabet.在字母表里A排在B之前(排列)。

五、before long与long before

before long是“很快,不久(以后)”的意思,等于soon,可以用于各种时态,例如:

Before long he got married.不久他就结婚了。

before的用法,before和after用法详解(3)

而long before是“很久以前”的意思,等于long long ago,一般用在过去时或过去完成时的句子里。例如:

I saw the film long before.我很久以前就看过这部电影。

另外,before在不同的语境中会产生不同的含义,学生、教师在学习、教学中要认真研究,加以甄别。例如:

Linda has grown into a beautiful girl before she knows it.不知不觉Linda已长成一个亭亭玉立的少女。

Do it before you forget.趁早动手,免得忘记。

Be a pupil before you become a teacher.先做学生再做老师。

Lucy desired no one for her husband before Charles Darnay.

Lucy非Charles Darnay不嫁。

I’ll shoot myself before I apologize to him.我宁死也不向他道歉。

The ship sailed before the wind.轮船顺风而行。

before的用法,before和after用法详解(4)

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