An aesthetics professor’s grandson asked his grandfather，"grandpa，why did you say that all the false are ugly?”

美学教授的孙子问他爷爷:“爷爷，为什么您说，一切假的都是丑的?”

"That is certainly true. Couldn't you give me an opposite example?”

“那当然了!难道你还能举出相反的例子来?”

“Oh，yes,"the grandson，climbing in his grandfather’s knee，said proudly，“Looking at yourself，when you put on your false teeth，you look younger and lively; when you get off them,you mouth looks empty and shriveled, which is really ugly Isn’t it an opposite example?”

“能!”孙子爬上爷爷的膝头，得意地说:“您瞧您自己一装上假牙后又年轻又精神，拿掉假牙，嘴巴又空又瘪，那才丑呢!这不是相反的例子吗?”

The professor could find no answer.

教授无言以对