Question

The boy _______ we saw yesterday is john's brother . 前面为什么不用that? 若果从句中没有主语，也就

是直接动词，能用that引导吗？

Answer 1

定语从句中，关系代词作宾语时，可以省略。

第二种情况中，关系代词作主语时，不可省略。

注：that 可以指代人或物。 这里也可以用who引导

追问

若果从句中没有主语，也就

是直接动词，能用that引导吗？

追答

定语从句中，不可能有无主句啊。引导词本身就作主语。如：

Some people who are successful language learners often fail in other fields .
有些在语言学习上很有成就的人,在其他领域常常一无所成。

追问

Some people who are successful language learners often fail in other fields .

就是这种句型，who后面直接加are，像这里能用that吗？

追答

可以的。that 代替人或物皆可

追问

都可以，除了特定的前面有anyone不定人称代词，介词+关系代词，用逗号隔开的，，，还有什么不用that的？？？

追答

一、关系代词直接放在介词后面时，要用which。例：
Read the passage to which I referred in my talk.
读一下我在演讲中提到过的那段文章。
His new car, for which he paid ￡7000, has already had to be repaired.
他花700英镑买来的那辆新车已经不得不修理了。

二.which还可以用作关系限定词，后跟名词，that则不能这样用。例：
He changed his mind for the second time, after which I refused ever to go out with him again.
他第二次变卦，以后我再也不跟他出去了。
The postman comes at 6.30 in the morning, at which time I am usually fast asleep.
邮递员早晨六点半就到，而这时我通常还熟睡着呢。
He may come, in which case I'll ask him.
他也许会来，来了我就问他。
There are 2 left, one of which is almost finished and the other of which is not quite.
剩下两件事，一件快做完了，另一件还有得做。

三、引导非限制性定词从句时，一般要用which，不用that。例：
Football, which is a popular game, is played all over the wofld.
全世界都踢足球，它是一项很受欢迎的运动。
She spent all evening talking about her latest book, which none of us had ever heard of.
她花了整个晚上谈她最近的新书，关于这本书，我们没有一个人听说过。

Answer 2

因为在定语从句中宾语，可以省略，这里省略了

Answer 3

当然可以啊!，这里用who,whom,that都行。但是the boy who is jhon's brother is tall.绝不可以用whom

Answer 4

that 可有可无 只起引导作用