If you are traveling the customs are really foreign to your own，please do as the Romans do.
A.in which B.what C.when D.where
If you are traveling the customs are really foreign to your own，please do as the Romans do.
A.in which B.what C.when D.where
D
where引导了地点状语从句。本题考生容易误选in which来引导定语从句。