I was doing my homework mother was cooking.A. when B. whileC. asD. what time

问题补充：

I was doing my homework mother was cooking.

A. when

B. while

C. as

D. what time

答案：

A. when

(答案→)B. while

C. as

D. what time

解析：when当……时；while当……时，一边……一边……；as因为，随着；what time什么时间。句意：当我的母亲正在做饭时，我正在做作业。While引导时间状语从句强调主从动作的同时发生，结合语境可知选B。