He tried to look younger than he is but his gray hair gives

He tried to look younger than he is but his gray hair gives he is ( )younger than you,but he looks ( )talle What does he look like?He has gray hair.And he is( )blue he is a little weak in this but he tried his best to catch u He is a little weak in this ,but he has tried his best to ca ---He has gray hair.And he is [ ] blue He is______taller than his younger sister. he looks younger ,but he is older than me -three years. She is two years younger than he. He tried his best to quit smoking but he failed.这个句子对吗?为什么 He tried his b___ to study,but still failed he exam. he looks younger than his real age 这句话对吗