问题补充:
He had collected plenty of historical evidence, proved that humans used to have different sleeping patterns.
A. that
B. which
C. it
D. what
答案:
A. that
(答案→)B. which
C. it
D. what
解析:考察定语从句。本题定语从句的先行词是plenty of historical evidence,后面的定语从句中的关系代词which指代先行词在句中作主语,that不能引导非限制性定语从句,it和what不能引导定语从句。句意:他已经收集了很多的历史证据,这些证据证明人类过去常常有不同的睡眠的方式。故B正确。