The fact _______ his health is bad is not true.A.which B.tha

The fact _______ his health is bad is not true.A.which B.that C.as D.what 各个选项间的区别.
不学英语好多年.都忘干净了.

The fact _______ his health is bad is not true.
A.which B.that C.as D.what 各个选项间的区别
which 作关系代词时引导定语从句,它要在从句中充当句子成份,如主语,宾语等等.
that作关系代词时的用法与which基本一样,在从句中要充当句子成份,但它还可以引导其它从句,如宾语从句,同位语从句等等.引导同位语从句时,它只是起引导作用,在从句中不充当句子成份,这点是有别于其它从句用法的关健.
as也可以作关系代词引导定语从句,引导定语从句时,它在句子中要充当句子成份.它还可以引导其它从句.
what作连接词时,主要引导名词性从句,如主语从句,宾语从句等等.
本句话中the fact在从句his health is bad中不起任何作用,从句意思已经完整,所以它只是起引导作用,所以用that,它是同位语从句.