引申是指从原词的内在含义出发，结合语境和译入语的表达习惯，在译文中对某些词作一定的语义调整，以达到忠实、通顺的目的。英译汉时常常会遇到许多单词，按词典上给的词义来翻译，译文就会生硬难懂，甚至造成意思上的曲解。因此，需对词义进行必要的变动，引申出能表达词语内在含义的新的表达方式。

引申既可化具体为抽象，也可化抽象为具体。

一、从具体到抽象

There were times when emigration bottleneck was extremely rigid and nobody was allowed to leave the country out of his personal preference.

分析：bottleneck本指瓶颈，由于具有使缓慢和阻滞的效果，因而被抽象地引申为限制。

参考译文：过去有过这种情况：移民限制极为严格，不许任何人出于个人考虑而迁居他国。

二、从抽象到具体

While there are almost as many definitions of history as there are historians, modern practice most closely conforms to one that sees history as the attempt to recreate and explain the significant events of the past.

参考译文：几乎每个史学家对史学都有自己的界定，但现代史学家们的观点都趋向于认为史学是试图重现并阐明过去发生的重大事件。