He is tall _for_ a boy _of__ ten.填这两个词语法上怎么解释呢?

He is as a tall boy as he is. He is as tall a boy as his brother.这句中的as tall a boy as不理解 The boy is so tall .I can hardly b ( )he is only ten years o 请问How tall a boy he is 为什么 e.g.He is a very tall boy. he a boy is tall(?)连词成句 he is a boy of ten 3Q If a boy is five tall, how tall is he in meters? He is a tall thin boy.(对画线部分提问)(画线部分是a tall thin boy)_ _ he He is a tall,thin boy.(对划线部分提问,划线部分为：a tall ,thin) He is a ( ) boy.A.five-foot tall B.five-feet tall C.five-foo he is a tall