It is a long time they separated but it won’t be long they meet again.A. since beforeB

问题补充：

It is a long time they separated, but it won’t be long they meet again.

A. since, before

B. after, when

C. since, when

D. after, before

答案：

(答案→)A. since, before

B. after, when

C. since, when

D. after, before

解析：句意：自从他们分开已经很长时间了，但是没过多久他们又相见了。Since自从，前面的主句也可用现在完成时；it won’t be long before…没过多久就…….这是固定句型。