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Everyone aboard the plane perished in the air crash.A. survivedB. disappearedC. diedD. left

单选题If headaches only occur at night, lack of fresh air is often the cause.

单选题The policeman stopped him when he was driving home and accused him of speeding.

单选题 The Natural Balance Being Altered The balance of nature is a very elaborate and delicate system of check and countercheck. It is continually being altered as climates change, as new organisms evolve, as animals or plants spread to new areas. But the alterations have in the past, for the most part, been slow. whereas with the arrival of civilized man, their speed has been multiplied much: from the evolutionary time-scale where change is measured by periods of ten or a hundred thousand years, they have been transferred to the human time-scale in which centuries and even decades count. Everywhere man is altering the balance of nature. He is facilitating the spread of plants and animals into new regions. Sometimes deliberately, sometimes unconsciously. He is covering huge areas with new kinds of plants, or with houses, factories, slagheaps and other products of his civilization. He gets rid of some species on a large scale, but favors the multiplication of others. In brief, he has done more in five thousand years to alter the biological aspect of the planet than has nature in five million years. Many of these changes which he has brought about have had unforeseen consequences. Who would have thought that the throwing away of a piece of Canadian waterweed would have caused half the waterways of Britain to be blocked for a decade? Or that provision of pot cacti for lonely settlers' wives would have led to Eastern Australia being covered with forests of prickly pears? Who would have predicted that the cutting down of forests on the Adriatic coast, or in parts of Central Africa, could have reduced the land to a semi-desert with the very soil washed away from the bare rock? Who would have thought that improved communications would have changed history by the spreading of disease- sleeping sickness into East Africa, measles into Ocean, AIDS around the whole world? These are spectacular examples, but examples on a smaller scale are everywhere to be found. We made a nature sanctuary for rare birds, providing absolute security for all species; and we may find that some common and hardy kind of birds multiplies beyond measure and drive away the rare kinds in which we are particularly interested. We see, owing to some little change brought about by civilization, the starting spread over the English countryside in hordes. We improve the yielding capacities of our cattle; and find that how they exhaust the pastures which were sufficient for less demanding stock. We gaily set about killing the carnivores that disturb our domestic animals, the hawks that eat our fowls and game-birds; and find that in so doing we are also removing the brake that restrains the multiplication of mice and other little rodents that gnaw away the farmers' profits.

单选题{{B}}第三篇{{/B}} Problems of the Elderly Gerontologists (老年人问题学者) study how old people are treated within a society and how the elderly deal with the inevitable problems of aging, particularly those involving health and income. Health problems include normal losses in hearing, eyesight, and memory, and the increased possibility of chronic(慢性的)diseases. These losses are gradual and proceed at different rates for each individual. In general, the health of old people today is better than that of earlier generation-a condition that is likely to improve still further as more people receive better medical care throught their lives. Because most old people are no longer in the labor force, a steady source of income is necessary. Systems of pensions and benefits are characteristic of industrial societies. One example is Social Security in the U. S. , which is now increased automatically as the cost of living rises, thus reducing somewhat the effect of inflation. Although the income of retired people is about half that of working people, most manage to remain financially independent. Income needs and health are what people consider most when they decide whether to re-tire or not. Putting an end to the limit on the retirement age is not expected to cause many workers to stay on the job if they can afford to retire. The need to relieve strains on the Social Security System, however, has led to legislation that gradually raises the age at which people can get full benefits. This might force them to work longer in the future. Elderly people themselves often display high spirits, satisfaction with life, and feelings of self-worth. The important factors are health and income. The task of modern societies is to ensure that the aged have their basic needs met and that they can continue to function in the community.

单选题Medieval cities grew rapidly when they had {{U}}harbors{{/U}} nearby.

单选题阅读下面这篇短文，短文后列出7个句子，请根据短文的内容对每个句子做出判断。 {{B}}Ancient Water From Afar{{/B}} It streaked across the sky on a warm March evening last year, then crashed into a street in the small town of Monahans, Texas. When seven boys quit their basketball game to inspect the damage, they found a shiny, black grapefruit-size rock settled in the asphalt (沥青). Word of the “flaming rock” traveled quickly in newspapers and on TV. The next day, NASA scientist Everett Gibson arrived and took the meteorite(陨石) , later named Monahans 1998, back to a lab in Houston. There researchers broke open the extraterrestrial (地球外的)rock with a hammer and chisel (凿子). To their surprise, they struck water. A team led by Michael Zolensky of the Johnson Space Center reports this discovery in a journal. It’s the first time anyone has found liquid water in an object from space—and a suggestion that life may exist out side our planet. Meteorites containing water are probably not scarce, Zolensky says. But by the time researchers get their hands on the rocks, minerals that trap the water have dissolved away, and the water have evaporated. Worse, some researchers destroy the evidence by cutting meteor ites open with rock saws and water. “I’m betting this isn’t such a rare finds it’s just that people have been mistreating their meteorites,” Zolensky says. Of course, Zolensky’s team did get a bit lucky. Monahans 1998 was safe in their lab less than two days after it hit the Earth, so they examined an unusually fresh sample. The scientists were keen to find vivid purple crystals of halite (岩盐)inside the meteorite, since halite is a salt mineral usually formed from liquid water. Even more curious were the hundreds of tiny bubbles suspended in the halite crystals. Zolensky’s team analyzed the bubbles by shining a laser beam through them and confirmed they were made of salty brine (盐水). By dating the halite, Zolensky’s team found the water trapped inside it formed at least 4.5 billion years ago, back when most scientists believe our solar system was born. That means the briny object amy help researchers learn about the gaseous nebulas(星云)that gave rise to our sun and planets. But how did the meteorite get wet? One possibility is that a passing comet smashed into the rock, dropping off a load of liquid water. Or the rock might have chipped off an asteroid (小行星)that holds pools of fluid. Zolensky’s team still needs to study whether the water comes from our own solar system. One thing is certain, however: the Monahans meteorite will fuel the debate on extraterrestrial life, “Water is a life-giver, so if you want to study where life came from in the solar system, you have to follow where water came from,” Zolensky says. A wet rock from space doesn’t mean little green men are coming soon to a planet near you, but it does raise hopes that we’re not alone in the universe.

单选题"Initial expectations were too great, "explained Alex Slawsby, senior analyst of mobile devices at IDC (International Data Company)of US. " It was a solution to a problem no one thought they had. " But now, helped by growing industry support, shipments of Bluetooth devices are expected to increase about 60 per cent in 2004 to 88 million units. That's up from 55 million sold in 2003, according to US research firm Gartner. How many units of Bluetooth were sold in 2003?A. 88 millionB. 55 millionC. 33 millionD. 60% more than the previous year.

单选题Did anyone{{U}} call {{/U}}me when was out?

单选题I can no longer tolerate his actions.

单选题The love of money is the root of all evil.A. resultB. endC. forceD. cause

单选题Experiments enable young scientists to judge accurately what must be accepted and what must be viewed with suspicion. A. doubt B. belief C. curiosity D. judgment

单选题We have to hurry up since we have no ______ time to finish it.A. sufficientB. additionalC. efficientD. consequent

单选题The polar {{U}}regions{{/U}} are generally covered with ice and snow.

单选题He confessed that he did not read the assigned book. A. answered B. agreed C. admitted D. alleged

单选题Nowadays, we can purchase things on-line. A. read B. buy C. rent D. watch

单选题The food we have is inadequate .

单选题Mary is Ulooking/U for the book she lost yesterday.

单选题The industrial revolution {{U}}modified{{/U}} the whole structure of English society，