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.