The rural workforce has been flowing in to the cities ever since the open door policy was adopted.
自从改革开放政策实施以来,农付劳动力正不断流向城市。
So archaeologists have neither history nor legends to help them to find out where the first 'modern men' came from.
于是,考古学家们既缺乏历史记载,又无口头传说来帮助他们弄清最早的“现代人”是从哪里来的。