条件状语从句，即满足某条件，动作才发生的句子。

条件状语从句的逻辑

最常见的条件状语引导词是if，还有unless, whether or not, in case (that), on condition that, provided, 还有隐含条件关系的but for，without等。

条件状语从句引导词

真实条件句，表现的是说话者的真正意图。

• If you study harder, you will enter a good college. 如果你更努力得学习，你就能考入好大学。

• If you love me, I will love you in turn. 如果你爱我，我将以爱回应你。

虚拟条件句，表示说话人的假设

• If you were to give birth to a baby, I would die. 你敢生老二，我就敢死。

生二胎得寻求老大的理解

• If he had arrived one minute later, she would have jumped. 如果他再晚来一分钟，她就可能跳下去了。
  

• I will not speak with you unless you cut the ties with her. 除非你和她断交，我不会跟你说话。

• Unless miracle happens, the factory will close. 除非发生奇迹，否则工厂得停业了。

• Chain reaction happens on condition that there is extremely high temperature and pressure. 只有在极端的高温高压的条件下，链式反应才会发生。

• This will will be valid on condition that the applicant is dead, 在申请人死亡的条件下，本遗嘱才能生效。

• She will not give you a glimpse whether you help her or not. 无论你帮不帮她，她都不会正眼瞧你。

• They will not betray his master whether you threaten them with death or not. 无论你用不用死亡威胁他们，他们都不会背叛他们的主人。