―Have you known Dr. Jackson for a long time?
―Yes, since she________ the Chinese Society.
A.has joined B.joins C.had joined D.joined
―Have you known Dr. Jackson for a long time?
―Yes, since she________ the Chinese Society.
A.has joined B.joins C.had joined D.joined
D
解析该句完整的句式是:I have known Dr. Jackson since she joined the Chinese Society. since后跟的时间状语从句要用一般过去时,表示自从过去某个时间发生的动作到现在以来有多长时间了。