We must apply what we have learned to our daily work because in no case _A__from practice.

题目

We must apply what we have learned to our daily work because in no case _A__from practice.
A should theory be separated B theory should be separated
C should theory separate D theory should separate
请详细解释下为什么选A.
顺便分析下这个句子的句子成分

答案

我们必须把我们学到的应用到实际生活中去,因为在任何情况下理论都不应该脱离实际.选a,因为前面有in no case ,所以用倒装.同时应该用被动,故选a