1．关系代词that与which的用法
(1)限制性定语从句中只用that不用which的情况：
①先行词是不定代词或者先行词被不定代词所修饰时，关系代词通常只用that。
Do you have anything that you want to say for yourself?
你有什么要为自己说的吗？
②先行词被序数词，形容词最高级，the only，the very，the just, the last等修饰时，关系代词通常只用that，不用which。
This is one of the most exciting football games that I have ever seen.
这是我见过的最激动人心的足球比赛之一。
This is the only thing that we can do now.
这是我们现在唯一能做的事情。
③先行词既有人又有物时，关系代词只用that，不用which。
The scientist and his achievements that you told me about are admired by us all.
我们所有人都钦佩你告诉我的那位科学家和他所取得的成就。
④定语从句出现在which或who的特殊疑问句中时用that。
Which is the bike that you lost?
哪辆是你丢的自行车？
⑤有两个定语从句时，其中一个关系代词宜用which，另外一个宜用that。
They secretly built up a small factory, which produced things that could cause pollution.
他们偷偷地建了一家小工厂，这家工厂生产可能会造成污染的东西。
⑥当先行词在主句中作表语，而关系代词在从句中作表语时
Shanghai is no longer the city that it used to be.
上海不再是过去的那座城市了。
