2. _______ 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
[思路点拨]
答案为A。主语从句she couldn’t understand 缺少宾语，要用what 引导。表语从句fewer and fewer students showed interest in her lessons 是一个完整的句子，要用why 引导。译文：为什么越来越少的学生对她的课感兴趣。故选A。
[注]：有时为了保持句子平衡，常用it作形式主语，放句首，用what连接的主语从句作真正主语放句末。
