By looking at the fossil record from that period of time - before the Red Sea was formed - we can gain a clearer view of which species survived this great migration and which did not.

通过观察这一时期——红海形成之前——的化石记录，我们就能更清楚地知道哪些物种在这次大迁徙中活了下来，哪些没有。

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These strategies have widely different characteristics with respect to migration effort and migration period, as shown in figure 1.

这些战略在迁移所需的工作量和迁移周期方面差异很大，见图 1。

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Rules on family migration (covering immigrants from outside the European Union) are entering a period of upheaval.

家庭迁移（从欧盟外的国家移入者）的规定进入了一个大的调整期。

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Migration data for the most recent one-year period available, July 2010 t0 July 2011, show the Great Recession has shaken the rankings up quite a bit within the circle of fast-growth regions.

FORBES: Where Americans Are Moving

This not only drives data revenues but also reduces churn, or the migration of smartphone users to competing carriers, as customers cannot change carriers before the expiry of the lock-in period.

FORBES: China Telecom Geared Up for iPhone Frenzy As Demand Boils