Question

定语从句中什么什么时候一定要用whom？

Answer 1

不管是在单独的疑问句中,还是在定语从句的关系词及名词性从句的引导词中,如果其做介词的宾语,且该介词和该代词放在一起,则此时只能用whom,不能用who。

如：

1.With whom are you talking?

此时只能用whom。

如果是：Who/whom are you talking with?则都可以。

2.I don't know with whom you are talking.

此时只能用whom。

如果是：I don't know who/whom you are talking with,则都可以。

3.Do you know the boy with whom I was talking just now?

此时只能用whom。

如果是：Do you know the boy who/whom I was talking with just now?则都可以。

Answer 2

一、不管是在单独的疑问句中,还是在定语从句的关系词及名词性从句的引导词中,如果其做介词的宾语,且该介词和该代词放在一起,则此时只能用whom,不能用who.
如：
1.With whom are you talking?
此时只能用whom；
如果是：Who/whom are you talking with?,则都可以.
2.I don't know with whom you are talking.
此时只能用whom.
如果是：I don't know who/whom you are talking with.,则都可以.
3.Do you know the boy with whom I was talking just now?
此时只能用whom；
如果是：Do you know the boy who/whom I was talking with just now?,则都可以.

二、如果句中已经出现了who,此时不宜再用who,如果不做主语,则改用whom.
如：Who is the boy (whom) you were talking with just now?
此时,不能写成：Who is the boy who you were talking with just now?