before是什么道理（before的用法长久说不够）

before是什么道理（before的用法长久说不够）

一、It be some time +before…

此句型要害有四种含意，辨别阐明如次：

1.该句中主句为未来时态，before从句为普遍此刻时态；主句为普遍往日时，从句常常也为往日的时态。

2.比方：

It will be some months before we graduate from school.(过几个月，咱们就结业了。)

Shall we see him again? (咱们还能见到他吗？)

I think so. It won’t be long before he comes back to the hometown.(我想会的，过不了多久他又归来故土。)

该句型中的功夫长为long, 口口网a long time, years, months, weeks, days, hours, minutes等功夫段。此句型简单与夸大句型污染，试比拟：

It was two years before he came back from abroad.(过了两年他才从海外回顾。)

It was two years later before he came back from abroad.(两年之后他才从海外回顾。)

第一句为状语从句，it 表白功夫；第二句为夸大句型，夸大的是功夫状语two years later。

3.该句型的扩充为“还没赶得及……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.(深夜里有人挂电话，然而我还没赶得及回复他就挂了。)

4.该句型再有一个扩充含意为“……之后才……”，多与连接性功夫、举措连用。比方：

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

二、“not…before”句型偶尔可换成“hardly…when…”或“scarcely…when”句型

比方：

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”句型道理沟通，表白“直到……才，在……往日不……”(即在否认句中，until 和 till 不妨和非连接性动词连用，这时候 until 和 before 近义)

比拟例句：

She stood there till/until he had passed out of sight.(不必before)他从来站在那儿，直到他消逝。

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

One doesn’t know the value of health before/until he loses it.人们遗失了安康后才领会安康的珍爱。

四、Before, after与behind

befo口口网re表功夫、程序或陈设时与after对立；表场所时与behin口口网d对立。比方：

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

Autumn comes before winter.秋去冬来(程序)。

A comes before B in the alphabet.在假名内外A排在B之前(陈设)。

五、before long与long before

before long是“很快，不久(此后)”的道理，即是soon，不妨用来百般时态，比方：

Before long he got married.不久他就匹配了。

而long before是“很久往日”的道理，即是long long ago，普遍用在往日时或往日实行时的句子里。比方：

I saw the film long before.我很久往日就看过这部影戏。

其余，before在各别的语境中会爆发各别的含意，弟子、教授在进修、熏陶中要刻意接洽，加以鉴别。比方：

Linda has grown into a beautiful girl before she knows it.人不知，鬼不觉Linda已长大一个亭亭玉立的女郎。

Do it before you forget.赶早发端，以免忘怀。

Be a pupil before you become a teacher.先做弟子再做教授。

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.我宁死也不向他抱歉。

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