问题 选择题

---Why is the classroom so dirty? 

--- Sorry, sir. It ______ yesterday. We forgot to do it.

A.doesn’t clean

B.didn’t clean

C.isn’t cleaned

D.wasn’t cleaned

答案

答案:D

根据yesterday,可知本题考查的是一般过去时的被动语态,故选D

单项选择题
单项选择题