1、 在“介詞+which/whom”結構中，關系代詞用which 還是用whom，取決于它前面的先行詞是物還是人。先行詞是物，用which；若為人，就用whom。如：

(1) Nearby were two ships in which they had come to the island.

(2) I can’t remember the name of the person to whom I gave the money.

2、這一結構用什么介詞取決于先行詞的意義和定語從句中謂語動詞結構及“介詞+which/whom” 在句中的作用。

(1) This is the room in which we lived last year.

(2) There were three people from whom we attempted to find out information.

3、 因為含有介詞的短語動詞一般不拆開，介詞仍放在動詞的后面。此種情況下關系代詞可用which, that, who, whom，或?qū)⑺麄兪÷浴?/strong>

(1) Is this the book (which/that ) she was looking for?

(2) The babies (whom /who/that) the nurse are looking after are very healthy.

4、表示地點、時間和原因含義的“ 介詞+which”結構可分別用關系副詞where, when和why替換。

(1) The earth on which /where we live is a planet.

(2) I’ll never forget the day on which /when I joined the League.

(3) Is there any reason for which /why you should have a holiday?

5、Of which可以代替whose 用來指物，其詞序一般為“名詞+ of which”

(1) They live in a house whose door/the door of which opens to the north.

(2) He has written a book whose name /the name of which I’ve completely forgotten.

6、“復雜介詞 in front of, at the back of, on the top of, in the middle of 等+ which”結構可引導非限制性定語從句。

(1) He works in a factory, in front of which there is a river.

(2) In the evening we arrived at a hill, at the foot of which there was a temple.

7、“介詞+which/whom”結構中的which和 whom不能替換為that，因為that不能做介詞賓語。如果用that，介詞必須反復到從句有關動詞的后面去。

(1) The room that/which he lives in is a small one.

(2) The room in which he lives is a small one.