His parents wanted to know what ____at that time?A.he was doing B.was he doingC.he is doingD.he has donewhy?
问题描述：
His parents wanted to know what ____at that time?
A.he was doing
B.was he doing
C.he is doing
D.he has done
why?
答
选A.解析:由题可知是由what引导的从句,应该用陈述句的语序,排除B.又因为前面的wanted是一般过去时,可知应该使用过去是的适当形式,排除C.由at that time可知应该使用进行时态,排除D.因此选择A.