问题补充：
I was doing my homework while my parents TV last night.
A. watched
B. were watching
C. have watched
D. are watching
答案：
A. watched
(答案→)B. were watching
C. have watched
D. are watching
解析：本题的含义是昨天晚上我正在做作业的时候，我的父母在看电视的事应该正在进行，所以while引导的从句用过去进行时，结构为be+doing，主语是复数，be用were，故本题选B。
