问题补充:
I want to know for the class yesterday morning.
A. why did you come late
B. why you came late
C. why do you come late
D. why you come late
答案:
A. why did you come late
(答案→)B. why you came late
C. why do you come late
D. why you come late
解析:本题know后跟的是一个宾语从句,用正常顺序,故不选AC,本题有过去的时间昨天上午,从句使用的是过去时,故本题选B。