It is bad manners to talk with your mouth full.

嘴里塞满了东西跟人说话是不礼貌的。

《牛津词典》

It is bad manners to stare at people.

瞪着眼睛看人是不礼貌的。

《新英汉大辞典》

Yes, it is bad manners to show up with an uninvited pooch.

是啊，带着一条未被邀请的狗出现确实是不礼貌。

youdao