---So you were in the supermarket you heard a strange sound right?---That’s true. I ran

问题补充：

---So you were in the supermarket you heard a strange sound, right?

---That’s true. I ran out as quickly as possible.

A. when

B. while

C. then

D. which

答案：

(答案→)A. when

B. while

C. then

D. which

解析：在超市里突然听到，when引导并列句相当与at that moment。