题干

Only after spending several nights working on the math problem         to wonder whether the problem was wrongly set.

A:had he begu

B:he bega

C:did he begi

D:began he

上一题 下一题 0.0难度 选择题 更新时间:2010-06-28 04:38:18

答案(点此获取答案解析)

C