If you are travelling the customs are really foreign to your own please do as the Romans

问题补充：

If you are travelling the customs are really foreign to your own, please do as the Romans do.

A. in which

B. what

C. when

D. where

答案：

A. in which

B. what

C. when

D. where

解析：考查地点状语从句：句意：如果你到文化风俗不熟悉的地方旅行，要入乡随俗。Where引导地点状语，相当于in the place where…,意思是：在…地方。选D。