想到一个好玩儿的对话，那时候我家姐姐上四年级，弟弟二年级。有一天，弟弟问姐姐：我还没见过你的sub teacher.

姐姐说：She's very pretty.

弟弟：That's just an opnion, not a fact.

姐姐：A lot of people say she's pretty.

弟弟：Like I said, that's just an opinion, not a fact, she could be in fact, you know, 

very ugly.