What you at this time yesterday?A. do doB. have doneC. were doingD. are doing

问题补充：

What you at this time yesterday?

A. do, do

B. have, done

C. were, doing

D. are, doing

答案：

A. do, do

B. have, done

(答案→)C. were, doing

D. are, doing

解析：考查时态：句意：昨天这个时候你在做什么？时间是at this time yesterday昨天的这个时候，是过去进行时的显性标志。表示过去某个时间正在做….选C。