问题
选择题
If you had joined the chat room ten minutes ago, you ______what we were talking about!
A．have known
B．knew
C．would have known
D．would know
答案
答案：C
考察虚拟语气的用法。根据If you had joined the chat room可知，该句是表示对过去的虚拟，主句选用would have done结构
句意为，如果你早十分钟进入聊天室的话，你就会知道我吗在讨论什么了。