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来源：雅诚德英语网
But was there one major wave of migration across the Bering Strait into the Americas, or several?
但是有没有一次或几次大移民浪潮是穿过白令海峡到达美洲的呢？
But was there one major wave of migration across the Bering Strait into the Americas, or several?
但是有没有一次或几次大移民浪潮是穿过白令海峡到达美洲的呢？