定語從句在下列情況下用that而不用which：

1，當先行詞為 all, anything, everything, nothing, something, few, little, much, any 等不定代詞時，如：

Do you have anything that must be claimed?

你有東西需要申報嗎？

I'll do all that is the party needs me to do well.

黨需要我幹什麼我就幹好什麼。

2，當先行詞被 all, any, little, no, few 等詞脩飾時，如：

There are few rules that have no exception.

很少規則沒有例外的。

All the poisons that are absorbed by the body are brought to the liver.

身體吸收的有毒物質都被送到肝臟。

3，當先行詞為形容詞最高級或被最高級脩飾時，如：

This is the highest score that I can get.

這是我所能取得的最高分數。

This is the most interesting book that I’ve ever read. 這是我讀過的最有趣的書。

4，當先行詞被序數詞脩飾時，如：

The first thing that needs to be done isto wash your hands when you go home.

當你回家時第一件要做的事是洗手。

The second approach that we’ve taken doesn’t work. 我們採取的第二種方法不起作用。

5，當先行詞為數詞或被數詞脩飾時，如：

The two articles that I recommend to you are written by Mark Twain.

我推薦給你的兩本書的作者是馬克·吐溫。

There are three that we found in that room.

我們在房間裡發現了三個人。

6，當先行詞被 the very, the only, the same, the last 等脩飾時，如:

He is the very man that we need .

他正是我們需要的人。

That's really the only thing that hurts.

只有這件事真的令我傷心。

7，當句子的主語為which 時，如：

Which is the product that we desire?

哪一個是我們所期望的產品？

8，當先行詞同時包含人和物時，如：

The old man and his daughter that we saw yesterday did not come here again.

昨天我們見到的那位老人和他的女兒沒有再來這裡。

從本質上理解，僅僅是定語從句脩飾的先行詞指示特別明確，不具備選擇性，就只能用that, 因為that 指的就是那一個，而which指的是哪一個。

1、先行詞是everything，anything等不定代詞時。2、先行詞被序數詞或最高級脩飾時。3、先行詞是並列結構，既有人又有物時。4、主句的主語是疑問詞who或 which時。5、先行詞前有the same脩飾時。