入乡随俗----Do in Rome as the Romans do.

例句：
A: What will you do If yon go to Tibet and live there for some time?
如果你到西藏去，并在那儿住上一段时间，你该怎么办？
B: There's no need to ask. I will do in Tibet as the Tibetans do.
用不着问，我会入乡随俗。

注释:
Rome (罗马）
Romans(罗马人）可按实际地方加以变化，如Tokyo(东京)和Tokyoites(东京人),Taiwan(台湾)和Taiwanese(台湾人)。