问题补充:
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:
A. asking
B. to ask
C. to be asked
(答案→)D. asked
解析:考查句子结构省略。在when引导的状语从句中,如果主语和主句的主语相同,而动词又是be动词的时候,主语与be动词往往被省略。此句省略了one be 完整的句子是when one is asked...,A表示进行时态,BC不定式表示将来,D在这里表示被动,句意是在课堂上被提问时,你回答问题要尽可能清晰。故选D.