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接時間狀語從句時要求時態一致并表示正在進行的動作，由于主句是一般過去時，故從句選用過去進行時。