she couldn’t understand was fewer and fewer students showed interest in her lessons.A. Wh

问题补充：

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

答案：

(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。