Scientists are convinced ________ the positive effect of laughter ________ physical and mental healt

题目简介

Scientists are convinced ________ the positive effect of laughter ________ physical and mental healt

题目详情

Scientists are convinced ________ the positive effect of laughter ________ physical and mental health.
A.of; atB.on; atC.by; inD.of; on
题型:单选题难度:中档来源:不详

答案

D

试题分析:第一空考查短语be convinced of的用法,意为:相信。第二空on意为:在……方面。句意:科学家们相信笑对身体和精神健康有积极作用。

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