He needs to be taught some manners. 他需要学些礼仪。
It's bad manners to eat with your mouth open. 张着嘴吃东西是不文雅的。
It's considered good manners in some societies to leave a little food on your plate. 在某些社会中,人们认为盘中剩下少许食物是礼貌的表现。
See also: manner (POLITE BEHAVIOUR)