When solving the problem a second time you’d better be more careful you made a mistake.A

问题补充：

When solving the problem a second time, you’d better be more careful you made a mistake.

A. in case

B. where

C. in which

D. that

答案：

A. in case

(答案→)B. where

C. in which

D. that

解析：句意：当你再次解决这个问题时，你一定要小心在你出现错误的地方。in case万一；这里是where引导的地点状语从句，所以不用in which来替换，它只有在定语从句中可以替换，这里没有先行词，不是定语从句。where在从句中作状语。根据句意故选B。