一个国家为了发展本国经济，经常要从国外引进一些物种，如我国的花生、玉米、蕃茄、咖啡、棉花、西瓜就是从国外引进的，而世界广泛种植的大豆、水稻、茶叶、荔枝、龙眼则是从我国引进的。优良物种的引进，对于丰富老百姓的餐桌，培育生物的多样性，发展本国的经济起到了很好 In order to develop their own economies, a country often imports some species from abroad. For example, peanuts, corn, tomatoes, coffee, cotton, and watermelons are introduced from abroad. Soybeans, rice, tea, litchi and longan are widely grown in the world. It was introduced from China. The introduction of excellent species has played a very good role in enriching the people’s table, cultivating the diversity of living creatures, and developing the country’s economy.