单选题
下面有3篇短文，每篇短文后有5道小题。请根据短文内容，为每题确定1个最佳选项。
{{B}}第一篇{{/B}}

Crop Problem

Advances in technology have helped more of the world's population live better and longer, and that is part of our problem[
Better health standards have kept larger number of people alive. The world's population is now almost four billion and expected to double in 25 years. Growing population and slowly rising living standards have increased our need for food at the rate of 30 million tons per year. As a result, the world's stockpile of food(食物储备) is declining by about 10 million tons per year.
From the early 1950s until 1972 ,world food production increased greatly. The Green Revolution (绿色革命) extended scientific techniques to agriculture in the form of hybrid seed (杂交种)and poultry (禽类), chemical fertilizers (化学肥料) and pesticides (杀虫剂), and complex irrigation systems. Strains (品种) of corn (玉米), sorghum (高粱), soybeans (大豆), wheat and rice were developed to flourish under particular climate and soil conditions.
In the United States, corn production rose to 110 bushels(蒲式耳：谷物、水果、蔬菜等容量单位，在英国相当于36,368升，在美国相当于35,238升) per acre from only 26 bushels per acre in the early 1900s. Milk production rose to 10,000 pounds per cow per year, compared with 600 in India. Chickens were bred to eat less, grow to maturity in shorter time, and produce more eggs. As a result of such scientific advances, our twelve midwestern states alone now feed one fourth of the world's people.
Crop disaster in 1972 brought an apparent end to the growth in production. Much of the extra yields had come from the use of chemical fertilizers, primarily petroleum based and now in short supply. The drop in world supplies of petroleum-based fertilizers is expected to cause a drop in crop yields of ten tons for each one ton decline in fertilizers applied.
This presents a particular problem for underdeveloped nations that often lack the foreign exchange necessary for buying fertilizer. The problem is so severe that Philip Handier, president of the National Academy of Sciences, has predicted one million child deaths per month in these nations by the year 2025.

单选题 The expected world population will reach ______ in 25 years.

单选题 What does the writer want to tell us in the paragraph 4.9

【正确答案】 D

【答案解析】[解析] 本题考查考生的理解判断能力，考的是对作者观点的理解。作者在第四段中以美国为例，告诉我们因为使用先进的技术，美国的谷物产量从20世纪的每英亩26蒲式耳增加到每英亩110蒲式耳；牛奶产量也增加到每头牛每年10,000磅，而印度每头牛每年只产600磅；用科学技术养鸡之后，鸡吃得少了，长得快了，下的蛋多了。随着这些科技的发展，仅美国中部12个州就可以养活全世界1/4的人口。由此我们不难推出，作者想告诉我们，美国使用科学技术使其粮食产量得以增加。所以，正确答案是D。

单选题 Judging from the passage ,the term "Green Revolution" refers to______.

【正确答案】 B

【答案解析】[解析] 本题考查考生根据篇章对特定短语的理解。考的是从文章中判断“绿色革命”指的是什么。从第三段我们可以得出，从50年代到70年代，全球粮食产量增长很快。绿色革命把科学技术通过各种形式应用于农业上，人们也研制了在特定气候和土壤下可以生长的玉米、高粱、大豆、小麦和稻子等新品种。因此绿色革命指的是科学技术在农业上的不断应用。所以，正确答案是B。

单选题 Given the present growth rate of the world's population and our ability to produce food______.

【正确答案】 C

【答案解析】[解析] 本题考查考生根据篇章的判断分析能力。考的是如果世界人口以目前的水平增长，我们的生产能力也保持现有水平，将会怎么样。从文章最后一段最后一句：The problem is so severe that Philip Handler，president，of the National Academy of Sciences，has predicted one million child deaths per month in these nations by the year2025. 我们可以得知，产量的问题已经非常严峻了，国家科学院院长Philip Handle预测，到2025年，在不发达国家里，每个月将有100万儿童死于饥饿。由此我们可以得知，如果世界人口以目前水平增长，而我们的生产能力保持现有水平，那么，我们将面临严重的粮食危机。所以，正确答案是C。

单选题 It is expected that crop yields will drop, especially in underdeveloped countries mainly because of______.

【正确答案】 C

【答案解析】[解析] 本题考查考生对细节的理解。考的是粮食产量，尤其是不发达国家的粮食产量下降的主要原因。本题的答案在第六段。由第五段我们可以得知，石油性肥料的紧缺可能导致粮食产量下降。第六段告诉我们，这对不发达国家来说更是个问题，因为这些国家没有足够的外汇来购买肥料。所以正确答案是C(财政匮乏)。