雅思阅读辅导：人类迁移美洲大陆的几个疑问

　　阅读段落

　　Recent work on the problem of when people first entered the Americas is an example of the value of these new techniques. North-east Asia and Siberia have long been accepted as the launching ground for the first human colonisers of the New World. But was there one major wave of migration across the Bering Strait into the Americas, or several? And when did this event, or events, take place? In recent years, new clues have come from research into genetics, including the distribution of genetic markers in modern Native Americans.

　　段落大意

　　本段介绍了人们能够利用基因研究人类迁移美洲大陆的几个疑问。

　　阅读笔记

　　Recent work show value of these new techniques

　　Major wave of migration across the Bering Strait?

　　When took place?

　　Research into genetics new clues

　　逻辑关系

　　1. 并列

　　But was there one major wave of migration across the Bering Strait into the Americas, or several?

　　When did this event, or events, take place?