问题
选择题
______ is often the case is that Tom doesn’t study hard and fails in passing an exam.
A．That
B．As
C．It
D．What
答案
答案：D
考察名词性从句。What引导主语从句What is often the case，并在句中作主语。本题容易错选B。as引导的是非限制性定语从句，指代一句话的内容在句中充当成分。