我今天在做英语阅读的时候看到一个句子为:
One day, the bombing stopped and the soldiers left. But the war was not over yet. Alia knew that if the books were to be safe, they must be moved again while the city was quiet.
我主要无法理解的部分为粗体字的含有条件状语从句的句子根据我们老师的话条件状语从句一定是主句情况发生的条件可是如果这么理解那就变成了“如果书安全了,那么它们就必须被再次转移”但根据上下文可知战争还没结束那么书安全就应该是被再次转移之后的事可这又不符合从句是主句条件的情况了我该怎么理解呢?