I am thirteen.Myfriend is fifteen years old.怎么合并成一个句子

问题描述:

I am thirteen.Myfriend is fifteen years old.怎么合并成一个句子

I am younger than my friend

这需要用到比较级了:
I'm two years younger than my friend.
或者:
My friend is two years older than me.
如果你没学比较级,就这样:
I am thirteen,and my friend is fifteen years old