问题补充：
.Most students used to listen to their teachers in class and completely obey their teachers，?
A. used they
B. weren’t they
C. didn’t they
D. did they
答案：
A. used they
B. weren’t they
(答案→)C. didn’t they
D. did they
解析：当陈述部分含有used to时，附加疑问句可用use(d)n’t或didn’t。
