He is at a place called Mamen.为何: 句中的 called 前面不加be动词以形成被动?

固定用法eg:it named changsha 被命名为....
这个是被叫做...

called是用来修饰place的，
与be无关。

词句应分为两部分看：
1.he is at a place
2.the place (is) called Mamen

定语从句，有省略，完整是He is at a place which is called Mamen.