Agriculture is the number one industry in the United States and agricultural products are the countrys leading export. American farmers manage to feed not only the total population of the United States, but also millions of other people throughout the rest of the world. Corn and soybean exports alone account for approximately 75 percent of the amount sold in world markets.
This productivity, however, has its price. Intensive cultivation exposes the earth to the damaging forces of nature. Every year wind and water remove tons of rich soil from the nations croplands.
Each field is covered by a limited amount of topsoil, the upper layer of earth which is richest in the nutrients and minerals necessary for growing crops. Ever since the first farmers arrived in the Midwest almost 200 years ago,cultivation and, consequently, erosion have been decreasing the supply of topsoil. In the 1830s, nearly two feet of rich, black top soil covered the Midwest. Today the average depth is only eight inches, and every decade another inch is blown or washed away. This erosion is steadily decreasing the productivity of valuable cropland. A United States Agricultural Department survey states that if erosion continues at its present rate, corn and soybean yields in the Midwest may drop as much as 30 percent over the next 50 years.
So far, farmers have been able to compensate for the loss of fertile topsoil by applying more chemical fertilizers to their fields; however, while this practice has increased crop yields, it has been devastating for ecology. Agriculture has become one of the biggest polluters of the nations precious water supply. Rivers, lakes, and underground reserves of water are being filled in and poisoned by soil and chemicals carried by drainage from eroding fields. Furthermore, fertilizers only replenish the soils they do not prevent its loss.
26. The last sentence in the first paragraph gives an example to show_______.
A. that American farmers manage to feed the total population of the U. S.
B. the leading position of the U. S. farming in the world
C. how important American people consider their farming
D. that many people in the world rely on the export of the agricultural products of the U. S. A.
27. In order to compensate for the loss of fertile topsoil, farmers have been_______.
A. planting less corn and soybean B. putting fertilizers on their fields
C. preventing soil erosion D. decreasing the supply of top soil
28. At the present rate, approximately how many years later the black top soil now covering the Midwest will completely be blown or washed away?
A. 120 years later. . B. 80 years later.
C. 50 years later. D. 100 years later.
29. This practice in Paragraph 4 refers to_______.
A. that farmers have lowered the yield of corn and soybean
B. that farmers have expanded croplands
C. that farmers have applied more chemical fertilizers
D. that the top soil has been decreased greatly
30. All of the following are statements about the disadvantages of fertilizers EXCEPT that
A. they replenish the soil B. they do not prevent the loss of soil
C. they are destroying the ecology D. they pollute the nations water supply
26. D 27. B 28. B 29. C 30. A
上一篇: 大学英语四级阅读模拟题(九)
体坛英语资讯:Color Run to launch Dream World Tour in 2017
2017届高考英语二轮复习大题冲关秘籍完形填空之记叙文:解题技巧(含解析)
2017届高考英语二轮复习大题冲关秘籍语法填空:创新押题(含解析)
2017届高考英语二轮复习大题冲关秘籍阅读理解七选五:名校模拟(含解析)
日本议会批准赌场合法化
2017届高考英语二轮复习大题冲关秘籍完形填空之夹叙夹议文:名校模拟(含解析)
油管人、巴马、脱欧:《牛津英语词典》又入新词
2017届高考英语二轮复习大题冲关秘籍完形填空之记叙文:创新押题(含解析)
2017届高考英语二轮复习大题冲关秘籍语法填空:命题分析(含解析)
2017届高考英语二轮复习大题冲关秘籍完形填空之记叙文:体验真题(含解析)
国内英语资讯:China to push agricultural reform
2017届高考英语二轮复习大题冲关秘籍短文改错:体验真题(含解析)
2017届高考英语二轮复习大题冲关秘籍阅读理解七选五:考纲解读(含解析)
国内英语资讯:President Xi urges supply-side structural reform in agriculture
川普上台后面临的经济挑战
2017届高考英语二轮复习大题冲关秘籍短文改错:解题策略(含解析)
国内英语资讯:China provides vehicles, equipment, supplies to Cambodias election committee
2017届高考英语二轮复习大题冲关秘籍语法填空:考纲解读(含解析)
Clickbait 点击诱饵
Interfere、meddle 和 intervene 三个表示“干涉、干预”近义词的区别
2017届高考英语二轮复习大题冲关秘籍语法填空:体验真题(含解析)
2017届高考英语二轮复习大题冲关秘籍之日常交际用语大全:高考英语日常交际用语必备习语大全(上)(含解析)
2017届高考英语二轮复习大题冲关秘籍短文改错:创新押题(含解析)
国内英语资讯:Xi meets Shenzhou-11 astronauts
2017届高考英语二轮复习大题冲关秘籍完形填空之记叙文:命题趋势(含解析)
2017届高考英语二轮复习大题冲关秘籍完形填空之夹叙夹议文:创新押题(含解析)
Do we need to attend lectures? 大学生是否需要听讲座式课程?
2017届高考英语二轮复习大题冲关秘籍短文改错:名校模拟(含解析)
体坛英语资讯:Clippers Blake Griffin to sit out 4-6 weeks due to knee surgery
国内英语资讯:Spotlight: Normalization of China-Norway ties to boost bilateral cooperation, global trade