Question

While I ________ with my friend, she came in.

1. A.
   am talking
2. B.
   was talking
3. C.
   talked
4. D.
   am going to talk

Answer 1

B
解析：
while接时间状语从句时要求时态一致并表示正在进行的动作，由于主句是一般过去时，故从句选用过去进行时。