这一疾病主要是通过采采蝇传播，在全世界最贫困的37个国家中流行。
The disease, transmitted mainly by tsetse flies, is prevalent in 37 countries among the poorest of the world.
第一种是以农业为主的国家，主要是非洲，那里的贫困人口集中在农村地区，他们的生产的马铃薯用于家庭消费和在当地市场出售。
The first is agriculture-based economies, mainly in sub-Saharan Africa, where the poor are concentrated in rural areas and produce potato for home consumption first and then sale to local markets.
第一种是以农业为主的国家，主要是非洲，那里的贫困人口集中在农村地区，他们的生产的马铃薯用于家庭消费和在当地市场出售。
The first is agriculture-based economies, mainly in sub-Saharan Africa, where the poor are concentrated in rural areas and produce potato for home consumption first and then sale to local markets.
应用推荐