All the recorded staple crops grown in westernAfrica were introduced from elsewhere, beginning, at some unknown date, with rice and yams.
西非所有从某个未知的日期开始记录的主要农作物都是从其他地方引进的,刚开始是种植水稻和山药。
2
On the other hand, rainfall increased in the interior of westernAfrica, and the northern limit of the tsetse fly, an insect fatal to cattle, moved south.
另一方面,西非内陆的降雨量增加,采采蝇活动区域的北部边界向南移动——一种对牛致命的昆虫。
3
The second largest rainforest is in WesternAfrica.