单选题 He is a writer, ______ is known to all.
A) that C) what
B) which D) this

【正确答案】 B
【答案解析】本题考点是非限制性定语从句。非限制性定语从句中不可用that来引导从句。本句大意：他是个作家，这是众所周知的。