Question

What ________ you ________ at this time yesterday?

A．did, do

B．have, done

C．were, doing

D．are, doing

Answer 1

C

试题分析：at this time yesterday,昨天的这个时间，过去进行时的标志。过去进行时的结构：was / were +V-ing .结合句意，昨天这个时候你正在干什么？故选C。