题干

I didn’t know his telephone number. ________ it, I ________ then.
A. Had I known; would ring him up    B. Should I know; would have rung him up
C. If I knew; would ring him up D. Had I known; would have rung him up
上一题 下一题 0.65难度 单项选择 更新时间:2017-08-10 11:10:02

答案(点此获取答案解析)