It's( )not his mother( )came across me last week

问题描述:

It's( )not his mother( )came across me last week
A him,whom B he,who C him,who D he,whom

B
这句话的意思是:是他不是他妈妈上星期遇见我.
他遇见我这个结构,他是主语,作主语的话要用主格,主格是he,(him是宾格,宾格做宾语).
who和whom也是,who是主格,作主语,whom是宾格,做宾语,come across后面的me是宾语,而它前面缺少主语,所以用who