--- It’s a long time I saw you last.
--- Yes, and what a pity. It will be a long time we see each other again.
A. before; since
B. since; before
C. when; when
D. since; when
网友回答
A. before; since
(答案→)B. since; before
C. when; when
D. since; when
解析：可联系答.案.网客服索取。