问题补充:
---How long each other before they married ?
---For about a year .
A. have they known ; get
B. did they know ; were going to get
C. do they know ; are going to get
D. had they known ; got
答案:
A. have they known ; get
B. did they know ; were going to get
C. do they know ; are going to get
(答案→)D. had they known ; got
解析:根据句意分析,他们结婚已是过去的事,那末,他们互相了解大约一年的时间肯定发生在结婚前,发生在过去某一动作之前的动作,应该使用过去完成时。