of the same age 或 of one's age，记住这两个短语。作表语或定语时，都可以省略 of。

作表语省略 of：

They are (of) the same age.

He is (of) the same age as me.

作定语省略 of：

Gary plays football with the other children (of) the same age.  

Unlike her friends (of) the same age, she is not afraid of the risk and enjoys exploring it.

of one's age，也是同样的用法，作表语、作定语举例：

Tom is (of) my age.

Tom is a boy (of) my age.