1. 当先行词被最高级、比较级或不定代词所修饰时,关系代词用that而不用which.但这条语法规律有个前提条件,即该定语从句是限制性定语从句.本题是非限制性定语从句,非限制性定语从句是绝对不能用that的,只能用whichwho, whom等.
2. 先行词被one of修饰,关系代词没有规定只能用that.退一步说,即使有这一条规定,本题的先行词也没有被one of所修饰,而是关系代词由one of所限定.
3. of是一个介词,介词后面只能用which, whom,不能用that.
4. 在下列几种特殊情况下,关系代词只用that,而不用which.
一、先行词被形容词最高级修饰时.如:
This is the most interesting book that I have ever read.(作宾语,可省略)
这是我曾经读的最有趣的书.
二、先行词被the very,the only等修饰时.如:
This is very book that I’m looking for.(作宾语,可省略)
这就是那本我正在寻找的不寻常的书.
The only thing that he could do was to wait paitiently.(作宾语,可省略)
他唯一能做的事情是耐心等待.
三、先行词被序数词修饰时.如:
The first thing that we do in the morning is to clean the classroom. (作宾语,可省略)
我们早上首先要做的事情是打扫教室.
This is the third largest city that was founded in the 1980s.(作主语)
这是在二十世纪八十年代被发现的第三大城市.
四、先行词是不定代词时.如:
Is there anything that I can do for you? (作宾语,可省略)
我能为你做什么事情吗?
He did all that he could to help me. (作宾语,可省略)
他竭尽所能地帮助我.
五、先行词是两个或多个分别表示人或物的名词.如:
He told us many interesting persons and things that we had never heard here. (作宾语,可省略)
他告诉了许多我们在这儿从来没听说过的有趣的人和事.
六、主语是以who,which 引导的特殊疑问句时.如:
Who is the man that was waiting for you? (作主语,不可省略)
那位正在等你的男子是谁?
Which is the teee that you planted three years ago? (作宾语,可省略)
哪一棵是你三年前种的树?
七、先行词是主语的表语或关系代词在从句中作表语时.如:
He is not the boy that he used to be.
他不是过去常常那样的男孩了.