问题
选择题
Scientists are convinced ______ the positive effect of laughter ______ physical and mental health.
A．of；at
B．by；in
C．of；on
D．on；at
答案
答案：C
题目分析：考查固定词组。固定词组be convinced of相信…；have an effect on…对…有影响；句意：科学家们相信微笑对于身体很精神健康都有积极的影响。故C正确。
点评：be convinced of相信…；have an effect on…对…有影响；对于形容词的短语搭配在平时的学习中也要注意识记和辨析。