which 與 that 在定語從句中 被稱為：關係代詞

which 引導定語從句時，先行詞是物，在從句中可做主語、賓語、表語

that 引導定語從句時，先行詞既可以是人，也可以是物，在從句中也可做主語、賓語、表語

關於which和that的常考點：

一、在限制性定語從句中，只能用that不能用which的情況：

1）當先行詞是指物的不定代詞

例：Do you have anything that you want to say for yourself?

2）當先行詞前面有下列詞修飾時：the only, the very, just, any, every, some等

例：This is the very busy that I’m waiting for.

3）當先行詞是形容詞的最高階或先行詞的前面有形容詞最高階修飾時

例子：This is the best that has been used against pollution.

4）當先行詞是序數詞或前面有序數詞修飾時

例：The train is the last that will go to Suzhou.

5）當先行詞既有人，又有物

例：Do you know the things and persons that they are talking about?

6）當主句的主語是疑問詞 who 或 which 時

例：which is the bike that you lost? Who is the boy that won the gold medal?

7）主句是there be句型且關係詞在從句中作主語時

例：there is a seat in the corner that is still available.

二、當先行詞指物，定語從句中只能用which不用that的情況：

1）在非限制性定語從句中，只能用 which

2）當動詞短語中的介詞提前時，只能用 which

3）先行詞後面有插入語時，只能用which.

例：Here is the English grammar book which, as I’ve told you, will help you improve your English.

4）先行詞本身就是that時

例：What’s that which flashed in the sky just now?