关系代词只能用that的几种情况

引导定语从句的关系代词that和which，在一般情况下，不管关系代词在从句中作主语或宾语都可替换使用。例如：

He bought a mobile phone that／which looks like a lighter．（作主语）他买了一个样子像打火机的手机。

I've found the book that／which he lost three days ago．（作宾语）我找到了他三天前丢的那本书。

但在下面几种情况下，引导定语从句的关系代词只能用that，而不用which：

1．先行词是复合不定代词everything，anything，nothing等时。例如：

She didn't forget anything that her mother had told her to buy．她没忘记妈妈让她买的任何东西。

注意：先行词是something时，关系代词用that或which都可以。例如：

I want to buy something that／ which the old men like to eat．我想买点老人喜欢吃的东西。

2．先行词被序数词或the last修饰时。例如：

This is the first textbook that I studied in the primary school．这是我在小学学的第一本教科书。

He is in the last row that is next to the window．他在挨着窗户的最后一排。

3．先行词被形容词最高级修饰时。例如：

That is the highest building that I have seen．那是我见到过的最高的大楼。

Have you worked out the most difficult maths problem that our teacher told us to do？你解出老师让我们做的那道最难的数学题了吗？

4．先行词是或被all，no，some，any，little，much等修饰时。例如：

I've written down all that（＝ what）the teacher doesn't allow us to do．我已记下了老师不允许我们做的一切事情。

They haven't got any dictionaries that we need．他们没有我们所需要的任何字典。

5．先行词被the only，the very，the same等修饰时。例如：

This is the very novel that you want to borrow．这就是你想借的那本小说。

注意：先行词被the same修饰时，关系代词也可用as。例如：

I need the same dictionary that／as you have．我需要同你的一样的字典。

关于as的用法，我们以后在高中阶段还会学到。

6．先行词是两个或多个分别表示人和物的名词时。例如：

He told us many interesting things and persons that we had never heard．他给我们讲了我们从没听到过的人和事。

7．主句是以who，which引导的特殊疑问句时。例如：

Who is the man that you spoke to just now？你刚才跟他说话的那个人是谁？

Which is the book that you want to borrow？你想要借的书是哪一本？

8．先行词是主句的表语或关系代词在定语从句中作表语时。例如：

China is no longer the country that it used to be．中国再不是以前那样的国家了。