she couldn’t understand was fewer and fewer students showed interest in her lessons.
A. What; why
B. That; what
C. What; because
D. Why; that
网友回答
(答案→)A. What; why
B. That; what
C. What; because
D. Why; that
解析：考查主语从句和表语从句：第一空填what，引导主语从句，主语从句中缺少宾语，第二空填why，是根据句意判断的：她不能理解的是为什么越来越少的学生对她的课感兴趣。选A。