當(dāng)“介詞+ which”在定語從句中作時(shí)間、地點(diǎn)和原因狀語時(shí)，可以用相應(yīng)的關(guān)系副詞when, where和why來替換。這些都是定語從句里面由which引導(dǎo)的定語從句，介詞提前。介詞的使用除了意思上的區(qū)別，具體是要以which引導(dǎo)的從句而定的。

in which, for which, on which, at which的不同用法

1)這些都是定語從句里面，由which引導(dǎo)的定語從句，介詞提前。下面這些介詞的使用除了意思上的區(qū)別，具體是要以which引導(dǎo)的從句而定的。

①in which可以翻譯成在……里面

The school (that/which) he once studied in is very famous.

= The school in which he once studied is very famous.

②for which可以翻譯成為了……目的

Tomorrow I will bring here a magazine (that/which) you asked for.

= Tomorrow I will bring here a magazine for which you asked.

③on which可以翻譯成在……的上面，或具體時(shí)間的某一天

I have a dresser in my bedroom, which there are many cosmetics on.

= I have a dresser in my bedroom on which there are many cosmetics.

④at which可以翻譯成在……里面或在……

The dumpling House which he often has dumplings at is very popular.

= The dumpling House is very popular, at which he often has dumplings.

2)當(dāng)然第一點(diǎn)只是介詞作為基本意思的用法，還有一些固定搭配，得具體情況具體分析。

①The plane may be several hours late, in which case there’s no point in our waiting.

(固定搭配：in the case)

②The speaker paused to examine his notes, at which point a loud crash was heard.

(固定搭配：at the point)

③Ten years of hard work changed her greatly, for which reason he could hardly recognize her at first sight.

(固定搭配：for the reason)

④The film at which I fell asleep was very boring.

(Here "at which" is based on "fell asleep at the film"因?yàn)殡娪盁o聊而睡覺。)

⑤The little creature in which scientists are interested is known as ET.

(這里"be interested in"是詞組原因)

⑥This is the book for which he is looking.

(即等于This is the book which he is looking for，這主要是因?yàn)閘ook for 這一短語)