You were late again this morning.Could you tell me()to you

问题描述:

You were late again this morning.Could you tell me()to you
A what happened
B what did happen
C what happens
D what was happening
B为什么不选?

从句要使用陈述句形式,所以排除B
 
选择A:what happened(已经发生过,使用过去时)