Question

______ on ten years of observation and study, the theory shows that every one dreams every night, whether they realized it or not.

A．Basing

B．Based

C．Being based

D．Having based

Answer 1

B

试题分析：考查非谓语动词作状语。句意：基于十年的观察和研究，这项理论表明，每个人每晚都做梦，不管他们是否意识到这一点。the theory与base之间是被动关系，故用过去分词作状语。选B。