Question

Researches are convinced ______ the positive effect of laughter ______ physical and mental health.

A．of; at

B．by; in

C．of; on

D．a(chǎn)t; on

Answer 1

C

試題分析：考查介詞：be convinced of相信…，第二空填on，effect on…對(duì)…的影響，句意：研究者相信，笑聲對(duì)身體精神健康的積極影響。選C。
點(diǎn)評(píng)：本題考查了介詞短語(yǔ)，在平時(shí)要加強(qiáng)識(shí)記和記憶。做題時(shí)要結(jié)合上下文判斷。