Question

【题目】_______ are playing an important part is well known to us all.
A.That who
B.Those who
C.Who that
D.Who

Answer 1

【答案】D
【解析】考查主语从句。句意：谁起着重要作用，这是众所周知的。主语从句缺少引导词，从句缺少主语，故选D。