宾语从句的问题:Bob,can you tell us______by saying that?
Bob,can you tell us__（B）___by saying that?
A.what do you mean
B.what you mean
C.you mean what
D.what did you mean
( 为什么不选D呢?by saying that是什么时态?什么情况?B中what后不是一个完整的陈述句啊!)