He thought he had already solved the problem,but that was not the _____.

题目

He thought he had already solved the problem,but that was not the _____.
A matter B case C condition D decisions
选B 为什么呢

答案

固定用法：
(not) the case,意思是‘（不是）真的’,(not) true,例如：
If that is the case then I will be very disappointed.如果那是真的,我会非常失望.
提问中的那句话的意思是：
他以为他已经解决了这个问题,但实际上没有.