问题补充：
If you the chat room ten minutes ago, you what we were talking about.
A. have joined ; will know
B. had joined ; would have known
C. should join ; would know
D. would join ; have known
答案：
A. have joined ; will know
(答案→)B. had joined ; would have known
C. should join ; would know
D. would join ; have known
解析：可联系答.案.网客服索取。
