题目

 Scientists are convinced ______ the positive effect of laughter ______ physical and mental health. A. of；on      B. by；in         C. of；at     D. on；at 答案：A下列各组词语中书写有误的一项是A.屏障 索利 过瘾 糯米B.难堪 商贩 蹲踞 藉贯C.秫秸 码头 凑齐 落幕D.衣襟 枸杞 门楣 煨炖