有这一句话：Lily is the same age as Mary.为什么是”is"而不是"has"

Lily is the same age as Lucy.改为同义句. Lucy is the same age as lily.的同义句 He has the same age as me还是He is the same age as me Tom is the same age as me.为什么不用has而用is呢? he is the same age as she is 为什么不说 he is as the same age as Lily is the same age as Lucy.(改为同义句） "she is the same age as you. Mary is as old as Kate.改为同意句 Mary has ___ ___ age ___ Kate. lucy is the same age as you are My cousin is the same age as me.同义替换! Jack is the same age as Ann. 解释句子 急用 John is about the same age as Tom.