一道关于宾语从句的题目

题目

一道关于宾语从句的题目
Just now he asked me________.
A.what was the matter with the computer
B.what was the girl's name
C.where did they have the meeting
D.when would we have final exams
我知道选A,what作主语,我的问题是：为什么B中的what不能作主语?

答案

the matter在这里相当于（wrong)adj
what is the matter?这里的what是个主语,be是系动词,the matter是个形容词的.
Is there anything the matter with you?
=Is there anything wrong with you?
B则应该是the girl's name作主语的.
The girl's name was what（what是表语）
又如：
I don't know who you are.who表语
I don't know what you are.what也是表语