Question

【题目】Scientists have advanced many theories about why human beings cry tears, none of________ has been proved.

A. whom B. which C. what D. that

Answer 1

【答案】B

【解析】考查定语从句。句意：科学家已经提出了许多关于人类为什么会流泪的理论，其中没有一个得到了证明。该句中的先行词是many theories，关系词在定语从句中作of的宾语，应该用关系代词which，none of which共同构成从句的主语，故选B 项。