he really doesn't know ___ at the meeting.

问题描述:

he really doesn't know ___ at the meeting.
A what to talk B how to talk about C what to talk about
选哪个,为什么?

选c
句意为:他真的不知在会议上该说些什么.所以排除b
what作talk的宾语,变换一下句式为talk about what,该用talk about sth句型.