i did't see you at the meeting yesterday.i think you ___ it beacuse it was very important to you.

问题描述:

i did't see you at the meeting yesterday.i think you ___ it beacuse it was very important to you.
A should attend
B should have attended
请问选哪个,为什么?

B,should have done是个固定句型,本应该.但是却没做