考点4 关系代词which和that的区别

在先行词是事物的限制性定语从句中，that和which一般可互换。关系代词that只引导限制性定语从句，不能引导非限制性定语从句。

1. 在限制性定语从句中只能用that，不能用which作关系代词的情况

（1）当先行词是everything, anything, nothing, all, none, few, little, some等不定代词时，或当先行词被every, any, all, some, no, little, few, much等词修饰时。

All that can be done has been done. 所有能做的都做了。

（2）先行词被序数词、形容词最高级、the only, the very, the last等词修饰时。

The first place that they visited in London was the Big Ben.

在伦敦他们参观的第一个地方是大本钟。

It’s the most important task that should be finished soon.

这是需要马上完成的最重要的任务。

（3）先行词既有人又有物时。

They talked about the persons and things that they remembered at school.

他们谈论了他们所能记起的在校时的人和事。

（4）当先行词前面有who, which等疑问代词时，为避免混淆，不用which而用that。

Who is the man that is standing by the gate? 站在门口的那个人是谁?

2. 只用which，不能用that作关系代词的情况

（1）在非限制性定语从句中只能使用关系代词which，不能使用关系代词that。

He made another wonderful theory discovery, which I think is of great importance to science. 他做出了另外一项精彩的发现，我认为这一发现具有重要的科学意义。

（2）在“介词+关系代词”引导的定语从句中，只能使用关系词which，不能使用that。

The house in which we live is very large. 我们住的房子非常大。

注意

如果介词不放在关系代词之前，which就可换为that。

This is the question about which we’ve had so much discussion.=This is the question which/that we’ve had so much discussion about. 这就是我们已经多次讨论过的问题。