3.表示原因的介词

for常常表示褒贬、奖惩的原因或心理原因。

They will reward you for your help.

due to常常用来引导形容词性的短语，作定语或表语。

Mistakes due to carelessness may have serious consequences.

from和out of常常表示动机或原因；through表示消极或间接的原因。

He feels weak from lack of sleep.

He broke down through overwork.

4.表示目的的介词

for表示拟定的接收人或目的；to表示实际的接收人或目的。

I bought the gift for my little sister.

I gave the gift to my little sister.

for和to都可以引导目的地。For跟在含有出发或开始意义的动词后，如：leave， set out，start， depart， sail等；to跟在含有来来往往地行动的意义的动词后，如：go， come， run ，walk，move， fly， drive， ride等。

We have left for Hong Kong.

He flew to America via Hong Kong.

at表示起因；on表示依据。

She is quite pleased at his help.

Ken was arrested on a charge of that.

at还可引导行为的目标或精力的集中点。

He shot at the bird.

5.表示“关于……”的介词

一般about用于比较随便的谈话或非正式的文体；on用于正式的讲话、著作或报告中；of用于动词talk， read， know， say， hear， boast等的后面。如：

What are you talking about？

A paper on serfdom in Russian

In terms of natural resources

6.表示原料的介词

of和out of表示制成品的材料仍保持原材料的性质；with表示制成产品的一种成分；from表示制成品已失去了原材料的性质；in表示制成品的材料的色调或特殊性。

His house was built of brick.

She made these toys out of old cigar-boxes.

A fruitcake is made with fruit.

Steel is made from iron.

We have furniture of this design in oak and in walnut.