Practice 1　　在农业科技领域中，中国正逐年缩小与发达国家之间的差距。科技进步对中国农业的贡献比率从1949年的20％增加到42％。农业科技部门在生物科技、高新科技和基础研究、植物细胞与组织培养方面取得了巨大进步，其中花粉培养、单倍体繁殖及其应用研究方面已经达到世界先进水平。双线性杂交水稻、杂交玉米的繁殖和体现集约耕种的多谷物套种技术也达到或者接近世界先进水平。另外，在利用杂交豆类的优点方面，研究也取得了重要突破。自从1949年，中国农业科学家们已培养了40余种农作物，5000种高产、质优、抵抗力强的新品种和新混合作物。主要农作物的品种已历经四到五代新产品了。一般而言，一代新产品将会增产10％——30％。现在，农作物产量从1950年每公顷l.16吨增加到4. 0吨，增产了2.8倍。

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In the sphere of science and technology related to agriculture, China year-by-year narrows the gap between its performance and that of the advanced countries. The contribution rate of scientific and technological progress to China’s agriculture has increased from 20 percent in 1949 to 42percent. Agricultural sci-tech departments have made much progress in biotechnology, new and high technology and basic research, and the cultivation of plant cells and tissues, anther culture, haploid breeding and the research on its application have reached the world’s advanced level. Bilinear hybrid rice, hybrid corn breeding, and multi-crop planting technologies featuring intensive cultivation have reached or approached the world’s advanced level. In addition, an important breakthrough has been made in the research of making use of the advantages of hybrid beans. Since 1949 Chinese agricultural scientists have cultivated more than 40 varieties of crops, and 5,000 high-yield, excellent-quality and strong-resistant new varieties and new combinations. The varieties of major crops have witnessed four to five renewals. In general, one renewal results in an increase of 10 percent to 30 percent in output. At present, the yield of crops has increased to 4.40 tons per ha from 1.16 tons per ha in 1950, or a growth of 3.8 times.

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