– What are your parents doing now?- Well my father is reading a newspaper my mother is co

问题补充：

– What are your parents doing now?

- Well, my father is reading a newspaper my mother is cooking.

A. after

B. while

C. but

D. then

答案：

A. after

(答案→)B. while

C. but

D. then

解析：while作为连词，连接时间状语从句，主句和从句的动作可以同时发生，都是用进行时。故选B