Question

This is the house where he was born

=This is the house in which he was born in =This is the house which he was born in 吗解释一下

Answer 1

This is the house where he was born
=This is the house in which he was born （in 提到前面去了，后面就别在出现了）
=This is the house which he was born in （不说 in which 而是把 in 放在后面，也是对的）

第一句中的 where = in which。这个 where 不同于我们平时常用的 where is he?中的疑问副词　where, 这里的 where，它等同于 in which，语法上叫做缩合连接副词。如果你有薄冰的《英语语法》，参看390页。

Answer 2

=This is the house in which he was born.

This is the house which he was born in.这种用法不常见

Answer 3

首先更正下，应该是This is the house in which he was born = This is the house which he was born in
这是定语从句的内容，where 和 which 是引导词，where= in the house, which= the house, in 是介词，表示方位，不是固定搭配，因此放前放后都可以。