My friend lives on the fifh floor of the building

问题描述:

My friend lives on the fifh floor of the building
on the fifth 划线部分提问.
___ ___ floor ___ your friend___.

On which does live
不懂追问*^__^* 为什么开头是Onon 也可以放后面, 但你前面有两空,这是就必须前置没有什么语法知识把