He looks much younger than he is.than后为什么会有主语和be动词

He looks much younger than he is.than后为什么会有主语和be动词 he looks()than you are A.younger D.much younger he looks much----- than he is he is ( )younger than you,but he looks ( )talle He looks younger than you are? He is(much)younger and stronger than you. 关于than的用法~She looks younger than she is.He runs a lot faster he looks younger ,but he is older than me -three years. She is two years younger than he. he is much older than me和he is more older than me有什么区别 She looks younger than she is.和She looks younger than she he looks younger than his real age 这句话对吗