题目内容：

改错Tom and(A)Mary took their(B) shoes in case of (C)they decided to go dancing
Tom and(A)Mary took their(B) shoes in case of (C)they decided to go dancing

优质解答

C 错误.
in case of 改成 in case.
in case of是为介词短语,其后不能加状语从句；
in case既可以单独使用,也可引导状语从句.