Question

【题目】_________ is generally believed, it is human activities that have contributed to the global warming.

A. It B. As C. that D. what

Answer 1

【答案】

【解析】

试题分析：考查定语从句。句意：人们普遍认为，正是人类活动导致了全球变暖。As在此处引导非限制性定语从句，指代逗号后面主句的内容，并在定语从句中充当主语。故选B项。