No matter how bright a talker you are, there are times when it's better silent.
A. remain
B. be remaining
C. having remained
D. to remain
网友回答
A. remain
B. be remaining
C. having remained
D. to remain
解析：it做形式主语，真正的主语是后面的不定式：to remain silent. 可归结为句型：it is +形容词/名词+to do/that…。当然it也可以做形式宾语，如find/feel it +to do/that….。