几个介词的惯用法

一般情况下，介词后面常接名词、代词或动名词等作宾语，而有时我们也见到介词+介词短语的现象，但并非任何介词都可以这样用。下面介绍几种常见的正确的这类用法。

1．frore+介词短语

①When I got to the house，a dog suddenly rllshed out from be-hind the door．

②The bov took out a ball from under the bed and went to theplayground in a hurry．

③He waved at me from across the street。

2．exceDt+介词短语

①I looked eveIywhere except in the bedroom．

②He UStlally goes to work by bike except on raining days．

③There was no direct route except through the centre of the city．

3．till／until+介词短语

①He won't g0 over his lessons till／unn’l before the examination．

②He watched TV till／untl’l afIer his father's return．

4．sinee+介词短语

①I have known Mr Wang since before liberation．

②He hasfl't come back to his home town sinee after his going tocollege．

5．instead of+介词短语

①He goes to work on foot instead of by bus．

②The teacher told his students to do their homework in class in―stead of at home．

介词for的用法很多，接名词时可以表示目的。接动名词可以表示原因，接动名词主语是物、谓语是be动词时常表示用途，等等。下面看一些常见例句。

Mother made a big cake for her son's birthday．(目的)

He was praised for saying a drowning hoy in the river．(原因)

The money is for buying clothes and food for orphans．(用途)

The train is leaving for Beijing．(方向、目标)

I won't be here for a week．(时间、距离、长度等)

It is a machine for sweeping the street．(作定语)

Here are some books for you t0 tead．(动词不定式的动作执行者

Are you for or against the plan?(赞成、拥护、愿望等)

介词for还可以表示动作，相当于动词意义，这在英语课本中可见到。例如：

N0t a11 ants go out for food(=to look for food)．

How much do you want for that(=t0 d0 that)?

I had to run for the bus(=to catch the bus)．

Mother went to the door to call everybody in for supper(=to havesupper)．

We were thirsty and he went home for some bottles of water(=tofetch some bottles of water).

She and her teammates als0 tried out for the relav race (=to takepart in the relay race)．

介词from除了接名词、代词作宾语外，还可以接副词、形容词、数词、短语或从句等作宾语。例如：

How far is it from here to the park? (副词)

He is far from pleased．(形容词)

Three from four leaves one．(数词)

You must stop the children from playing on the street． (动名词短语)

From what I have heard，you are to blame．(从句)

until和till词性和词义都相同，用法也基本相同，但要注意，在肯定句中和持续性动词连用，表示某动词持续到某时为止：在否定句中和终止性动词连用，表示“直到……才……”的意思。另外，till不可用在句首。例如：

I’ll stay here till／until ten o’clock。

He won't return till／until the dau after tomorrow．

Until then，I knew nothing at all about it．