答案:(1) vastness of the nation;(2) generosity of nature: abundant land and ideal weather;irrigation: abundant rainfall, rivers, and underground water;(3) mechanization: effective use of machines, fertilizers and chemicals; highly mechanized and productive;(4) readiness of many farmers to adopt new technology. They use computer to cut costs and improve productivity;(5) large-scale nature of agricultural enterprise: agribusiness (农业综合企业/农业产业化).