问题
选择题
When ________ questions in class, one should answer them as clearly as possible.
A．asking
B．to ask
C．to be asked
D．asked
答案
答案：D
本题考查省略。句意：课堂上被提问时，应尽可能清楚地回答。本句前半句实际上是when one is asked questions in class的省略。C项表示“将要被提问”，不合乎语境。