Their migration may have been set in motion by an increase in population caused by a movement of peoples fleeing the desiccation, or drying up, of the Sahara.

他们的迁徙可能是人口增加引起的，这一人口增长是由人们逃离撒哈拉沙漠的干燥或干涸的迁移造成的。

youdao

The consistent eastward movement of the songs is another puzzle, but the scientists speculate that the larger population near eastern Australia might have greater influence.

持续东传的歌声是另一个谜，但科学家们推测东澳大利亚的种群更大影响力可能也更大。

youdao

It is engraved with a commitment made to the Olympic Movement by a country that has 56 ethnic groups and a population of 1.3 billion.

这方“中国印”镌刻着一个有着十三亿人口和五十六个民族的国家对于奥林匹克运动的誓言；

youdao

And,this constant movement of population also affects the humanitarian workers as it makes the planning and the delivery of aid much more difficult because we cannot predict where the people are going or if they are coming back."

VOA: standard.2009.06.21

" ...such as relatively low levels of malaria risk to start with, political stability, a good health system and low levels of population movement bringing in infections from elsewhere."

VOA: special.2010.11.03

Mr White said over the past 10 years there had been a constant movement of population from the "Donegal side of the Foyle" to the east bank and other parts of Northern Ireland.

BBC: News - Fears over Protestant exodus from Derry west bank

"This significant move not only allows for free movement of the population, but also opens up this key supply route and allows for the provision of humanitarian aid, " it said in a statement.

BBC: Somalia: Mogadishu to Baidoa road 'reopened'

Siberia is sparsely inhabited because of a worldwide trend of population movement to cities, and because it is part of a very large country with a proportionally very small population.

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