Question

Something ________ you don’t know is very important.

A. that
B. where
C. what
D. it

Answer 1

答案A
此题考查定语从句的引导词。本句先行词something表示物，物做先行词时，定语从句的引导词用that或which。而当先行词是不定代词时，用that而不用which引导定语从句。故正确答案是A。