共用题干第二篇Are These Food Safe to Eat?Traditionally,in plant breeding,there are crossing varieties of the same species in ways they could cross naturally.For example,disease-resistant varieties of wheat have been crossed with highyield wheat to combine these

共用题干 What's Killing the BatsFirst it was bees.Now it is bats.Biologists in America are working hard to discover the cause of the mysterious deaths of tens of thousands of bats in the northeastern part of the country.Most of the bats affected are the common little brown bats(Myotis lucifugus,)but other species, such as the long-eared bat,the small-footed bat,the eastern pipistrelle,and the Indiana bat have also been affected. In some caves,more than 90 percent of the bat populations have died.One possibility is disease. A white fungus（真菌）known as fusarium has been found on the noses of both living and dead bats.However,scientists don't know if the fungus is the primary cause of death,a secondary cause of death,or not a cause at all,but the result of some other conditions.Another possible cause is a lack of food.For example,bats typically eat a large number of moths（蛾）,and in some states such as New York,the number of moths has been declining in recent years. if bats can't eat enough food,they starve to death.Still other scientists believe that global warming is to blame.Warmer temperatures in recent years have been waking up hibernating（冬眠）bats earlier than usual. If bats break their hiberna- lion at the wrong time,they might not find their expected food sources. The weather might also turn cold again and weaken or kill the bats.Scientists might not agree on the causes of the bat die-off, but they do agree on the conse- quences. Bats are an important predator of mosquitoes:a single brown bat can eat 1,000 or more insects in an hour. They also eat beetles and other insects that damage plant crops.If there aren't enough bats,damage will be great from the insects they eat. While bats live a long time for their size-the little brown bat can live for more than 30 years-a female bat has only one baby per year,so bat populations grow slowly. Many bat species in the United States are already protected or endangered.How can you help?Do not disturb sleeping or nesting bats.If you discover bats that seem to be sick or that are dead,contact your local Fish& Wildlife Department with the details.However, be careful not to touch the animals. What is the main idea of this passage?A: All species of bats in North America are dying.B: Scientists already know the cause of the deaths of bats.C: The bat deaths are a serious problem.D: There are many possible causes of the deaths of bats.

单选题Exports are either raw materials or manufactured goods. Raw materials are products of the land， such as cotton， timber or rubber. Some raw materials， such as iron ore， come from mines. These raw materials are often exported by the countries that produce them to other countries where they are made into manufactured goods. Some countries produce food for export， for example， meat， sugar， or cereals such as wheat and maize. These countries are agricultural countries. An agricultural country needs fertile land and a good climate. A cold， dry climate is not suitable for agriculture. A country which produces manufactured goods is known as an industrialized country. An industrialized country cannot always produce enough food for its own needs. In this case， it does not export foodstuffs. Instead it has to import them. It relies on exports of manufactured products and pays for imports with the money it earns from the exported goods. The countries which produce food for export, for example, meat, sugar, or cereals such as wheat and maize are countries.（）A developedB industrialC agricultural

单选题Which of the following is most clearly similar to a cline as it is described in the second paragraph of the text?A A vegetable market in which the various items are grouped according to place of origin.B A wheat field in which different varieties of wheat are planted to yield a crop that will bring the maximum profit.C A flower stall in which the various species of flowers are arranged according to their price.D A housing development in which the length of the front struts supporting the porch of each house increases as houses are built up the hill.

问答题Practice 1　　Genetic researchers have accelerated a plant’s growth by making its cells split faster—a technique that could someday lead to healthier crops, shorter growing seasons and less use of herbicides. One outside scientist called the findings astonishing. But the technique needs more testing on a range of plants, and public fear of genetically modified food is jeopardizing support for such experiments, especially in Europe, researchers said. The experiment, reported Thursday in the journal Nature, was carried out by a team at Cambridge University. The researchers first took a gene promoting cell division from inside the Arabidopsis plant, a flowering weed often used for genetic experiments. They transplanted that gene into a tobacco plant. There, in an especially potent form, the gene produced large amounts of a protein that, in combination with other chemicals naturally in the tobacco, made the plant’s cells divide more quickly at the tips of roots and shoots. Within a month after planting, the altered tobacco grew as much as twice as tall as other tobacco plants. Ultimately, the other plants caught up, and both groups then appeared identical in all ways. “It’s sort of like they’ve been able to make the plant go full throttle,” a said plant growth biologist John Schiefelbein at the University of Michigan. The leader of the study, Claire Cockcroft, said it is conceivable that the technique could be transferred to other species. Such plants, which probably would take years to develop commercially, might allow an extra planting in some climates or the introduction of crops in places where the growing season is too short, researchers said. The quick-growth plants would presumably take hold more easily, requiring less chemical herbicide to knock out weeds. Such plants might make easier and cheaper sources of some drugs.　　In scientific circles, the British research may also help settle an intense debate over what makes plants grow. Some argue, like these researchers, that something at the cellular level switches on growth; others look to hormones or other chemicals at a higher level of the plant’s makeup. “This is astonishing. Normally you would expect growth regulation to be more complicated,” said plant researcher Xuemin Wang at Kansas State University. “This has huge implications in terms of how we look at plant growth.” Biotechnology companies have genetically manipulated fruits and vegetables to make them more attractive or resistant to insects and disease. Genetic work has shown some early promise for faster growth, too. But previous attempts to boost growth through faster cell division have produced more cells—but smaller ones—and no overall growth. Scientists said such work is safe, with little chance of accidentally turning an unwanted plant into a fast-growing weed. After all, crops have been selectively bred for decades to bring out certain traits. However, ethicist Jeffrey Burkhardt at the University of Florida’s Institute of Food and Agricultural Sciences said selective breeding takes perhaps 15 years, giving scientists ample time to see the implications. “With the new biotechnology, you’re potentially moving traits in and　　out within a year,” he said.

共用题干第一篇Food PoisoningFood sometimes gets poisoned with harmful things,A person who eats such food can get an illness called food poisoning. Food poisoning is usually not serious,but some types are deadly.The symptoms of food poi- soning usually begin within hours of eating the poisoned food.Fever is one of the most common symptoms.Certain microorganisms（微生物）cause most types of food poisoning. Bacteria and other microorganisms can poison eggs,meat,vegetables,and many other foods.After entering the body,these tiny living things re- lease（释放）poisons that make people sick.Some chemicals can also cause food poisoning. They are often added to food while it is being grown,pro- cessed,or prepared.For example,many farmers spray chemicals on crops to kill weeds and insects.Some people may have a bad reaction to those chemical、when they eat the crops.Some plants and animals contain natural poisons that are harmful to people.These includo certain kinds of seafood,grains,nuts,seeds,beans,and mushrooms.When people handle food properly,the risk of food poisoning is very small.Microorganisms multiply rapidly in dirty places and in warm temperatures.This means that people should never touch food with dirty hands or put food on unwashed surfaces.Food should be kept in a refrigerator to stop microorganisms from growing, Meat needs to be cooked thoroughly to kill any dangerous microorganisms. People should also wash food covered with chemicals before eating it.Finally,people should not eat wild mushrooms or other foods that grow in the wild.Some of these foods may contain natural materials that are poisonous to humans.In addition,some types of fish can be poisonous.Most people recover from food poisoning after a few days of resting and drinking extra water. If people eat natural poisons,they must go to the hospital right away to have their stomachs emptied. Which of the following statements is NOT true?A:Food when poisoned can make people sick.B:Food poisoning means death.C:F0od poisoning comes in varieties.D:Food poisoning can be serious,

共用题干第三篇Sugar Accelerate the Process of AgingSugar is widely used in our daily life to make food and drinks sweet,though too much intake of it may lead to diabetes.However,today's study found it also makes people get old faster. Rats that eat high levels of a natural sugar known as fructose seem to age faster than other rats.And the same could be true for people who eat too much sweet junk food,said Israeli researchers.Fructose,a substance found naturally in honey and fruit,is used widely in foods ranging from soft drinks to yogurt. But while its sweet taste is popular,the sugar could cause wrinkles and health problems,the researchers said.Dr. Moshe Werman and Boaz Levi of the Technion-Israel Institute of Technology fed large amounts of fructose to laboratory rats.Writing in the Journal of Nutrition,they said the fructose-fed rats showed changes in the collagen of their skin and bones.Collagen,a fibrous protein found in connective tissue,bone and cartilage,basically holds the body together. The loss of collagen is what causes sagging and deep wrinkles in older people.The process affected,Werman's team said,is known as"cross linking"."Too much crosslinking reduces elasticity and makes the skin stiff and rigid,and these are the conditions that encourage wrinkled skin,"Werman said in a statement. He said the same could be true of people, although this has not been shown."Americans are eating more and more processed foods such as carbonated drinks,baked goods,canned fruits,jams and dairy products that contain fructose," Werman said.Other studies have shown that high fructose intake can affect how the body handles glucose and increases insulin resistance一which can both be important measures of the tendency toward diabetes.The rats Werman worked with were fed much more than the average adult person might eat in a day,which is standard in such experiments.The rats were 12.5 grams of fructose per kg(2.2 pounds)of weight every day for a year. To compare,a person weighing 154 pounds(70kg)who drinks a quart(liter)of cola consumes about 60 grams of fructose,or 0.8 grams per kg of body weight.Where are people likely to find fructose?A:Beans and wheat.B: Soft drinks and yogurt.C:Salmon and potato.D:Radish and pepper.

问答题The Truth about Genetically Modified Food　　At almost every public lecture I give, someone asks me my opinion on genetic modification—whatever be the topic of the lecture. Genetic modification (GM) has the power to save lives through its use in medicine, such as the production of insulin for diabetics or the treatment of genetic disorders. The current outcry comes when it is used to produce food.　　Some of these public concerns reflect real problems, but others are fuelled by misinformation and overdramatisation.　　There is nothing new about crop modification; plant breeders have been doing it since agriculture began. The wonderful range of apples or potatoes we now enjoy is the result of crossing different varieties. Cabbages, Brussels sprouts, cauliflower, kohlrabi, kale and broccoli all originated from one botanical species.　　Modern molecular biology has enabled us to go much further. We can now isolate the gene for a particular characteristic of an organism and transfer it to another species. It is this practice of transforming a plant with alien genes—perhaps from an animal or bacterium—that is causing all the controversy.　　There are three main concerns.　　Scientists can now take a gene for resistance to a particular herbicide and transfer it to a crop: when these plants are sprayed with weed-killer, the weeds are destroyed while the crop is unharmed. A prime concern is the harmful effect this could have on the biodiversity of farmland, where so many insects, birds and other animals depend upon “weed” species.　　Another fear is that alien genes from a GM plant could escape into a wild population of a related species. Since plants are fertilized by pollen that is carried through their, often for great distances, this is entirely possible. A wild species modified in this way with pesticide resistance could become a “super-weed”, while a species that becomes unnaturally resistant to animals that feed on it could disrupt the food chain.　　The third worry concerns a proposal to produce seeds for cereals that cannot germinate to produce next year’s seeds. This “terminator technology” would be of obvious advantage to seed companies, since farms would be forced to buy new weed annually.　　But the same technology could be devastating to some farmers in the developing world who depend upon saving some seeds for next year’s crop. Fortunately this technology is not yet in use and there has been strong pressure to abandon it.　　I would not hesitate to eat a GM vegetable—it is most unlikely that the current modifications are harmful to the consumer, despite what we read in the press. However, the introduction of animal genes into food plants presents considerable ethical difficulties to vegetarinsarians and member of religious that forbid the eating of certain animals.　　This is one of the reasons people are demanding that tall genetically modified food products be clearly labeled. The public have a fight to know what they are eating and a fight to choose.　　I believe that in my own nation GM is well regulated, but this cannot be said for some other countries. One of the problems is that at the moment this technology is commercially motivated. Because the compositions developing GM food want to introduce it as quickly as possible, in my opinion, it is being rushed into without adequate research or precautions.　　Genetic’ modification is here to stay, and there is no doubt it will save lives. But ,like so many other scientific discoveries, such as splitting the atom, it can be seriously misused. Instead of condemning the technique, we, should ensure it is used wisely. We need to evaluate each application carefully, from environmental and ethical standpoints, and we must urge governments and companies to use it for good rather than for greed.

共用题干 What's Killing the Bats?First it was bees .Now it is bats.Biologists in America are working hard to discover the cause of the mysterious deaths of tens of thousands of bats in the northeastern part of the country.Most of the bats affected are the common little brown bats(Myotis lucfugus),but other species, such as the long-eared bat,the small-footed bat,the eastern pipistrelle,and the Indiana bat have also been affected.In some caves,more than 90 percent of the bat populations have died.One possibility is disease. A white fungus（真菌）known as fusarium has been found on the noses of both living and dead bats.However,scientists don't know if the fungus is the primary cause of death,a secondary cause of death,or not a cause at all,but the result of some other conditions.Another possible cause is a lack of food.For example,bats typically eat a large number of moths（蛾）,and in some states such as New York,the number of moths has been declining in recent years.If bats can't eat enough food,they starve to death.Still other scientists believe that global warming is to blame.Warmer temperatures in recent years have been waking up hibernating（冬眠）bats earlier than usual. If bats break their hibernation at the wrong time,they might not find their expected food sources.The weather might also turn cold again and weaken or kill the bats.Scientists might not agree on the causes of the bat die-off,but they do agree on the consequences.Bats are an important predator of mosquitoes;a single brown bat can eat 1,000 or more insects in an hour. They also eat beetles and other insects that damage plant crops.If there aren't enough bats,damage will be great from the insects they eat.While bats live a long time for their size-the little brown bat can live for more than 30 years-a female bat has only one baby per year,so bat populations grow slowly. Many bat species in the United States are already protected or endangered.How can you help?Do not disturb sleeping or nesting bats.If you discover bats that seem to be sick or that are dead,contact your local Fish&Wildlife Department with the details.However,be careful not to touch the animals. The“moths”in Paragraph 3 are taken as an example of______.A: diseases that kill batsB: insects that bats eatC: animals that have diseasesD: bat species that are starving to death

共用题干 What's Killing the BatsFirst it was bees.Now it is bats.Biologists in America are working hard to discover the cause of the mysterious deaths of tens of thousands of bats in the northeastern part of the country.Most of the bats affected are the common little brown bats(Myotis lucifugus,)but other species, such as the long-eared bat,the small-footed bat,the eastern pipistrelle,and the Indiana bat have also been affected. In some caves,more than 90 percent of the bat populations have died.One possibility is disease. A white fungus（真菌）known as fusarium has been found on the noses of both living and dead bats.However,scientists don't know if the fungus is the primary cause of death,a secondary cause of death,or not a cause at all,but the result of some other conditions.Another possible cause is a lack of food.For example,bats typically eat a large number of moths（蛾）,and in some states such as New York,the number of moths has been declining in recent years. if bats can't eat enough food,they starve to death.Still other scientists believe that global warming is to blame.Warmer temperatures in recent years have been waking up hibernating（冬眠）bats earlier than usual. If bats break their hiberna- lion at the wrong time,they might not find their expected food sources. The weather might also turn cold again and weaken or kill the bats.Scientists might not agree on the causes of the bat die-off, but they do agree on the conse- quences. Bats are an important predator of mosquitoes:a single brown bat can eat 1,000 or more insects in an hour. They also eat beetles and other insects that damage plant crops.If there aren't enough bats,damage will be great from the insects they eat. While bats live a long time for their size-the little brown bat can live for more than 30 years-a female bat has only one baby per year,so bat populations grow slowly. Many bat species in the United States are already protected or endangered.How can you help?Do not disturb sleeping or nesting bats.If you discover bats that seem to be sick or that are dead,contact your local Fish& Wildlife Department with the details.However, be careful not to touch the animals.A: diseases that kill batsB: insects that bats eatC: animals that have diseasesD: bat species that are starving to death

共用题干 Natural FoodIncreasingly,over the past ten years,people一especially young people一have become aware of the need to change their eating________(51),because much of the food they eat,particularly processed foods,is not good________(52)the health.Consequently,there has been a growing ________(53)in natural foods;foods which do not________(54)chemical additives and which have not been________(55)by chemical fertilizers,widely used in farming today.Natural foods,for example,are vegetables,fruit and grain which have been grown in soil that is rich in organic matter. In simple________(56),this means that the soil has been________ (57)by unused vegetable matter,which provides it with essential vitamins and minerals________ (58)in itself is a natural process compared with the use of chemicals and fertilizers,the main ________(59)of which is to increase the________(60)(but not the quality)of foods grown incommercial farming areas.Natural foods also include animals which have been________(61)to feed and move freely in healthy________(62).Compare this with what happens in the________(63)production of poultry （家禽）:there are battery farms,for example,where thousands of chickens live crowded together in one building and are fed________(64)food which is little better than rubbish.Chickens kept in this way are not only tasteless as food;they also produce eggs which________(65)important vitamins._________(52)A:to B:withC:for D:about

共用题干第二篇Are These Food Safe to Eat?Traditionally,in plant breeding,there are crossing varieties of the same species in ways they could cross naturally.For example,disease-resistant varieties of wheat have been crossed with highyield wheat to combine these

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共用题干 第二篇Are These Food Safe to Eat?Traditionally,in plant breeding,there are crossing varieties of the same species in ways they could cross naturally.For example,disease-resistant varieties of wheat have been crossed with highyield wheat to combine these

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共用题干第二篇Are These Food Safe to Eat?Traditionally,in plant breeding,there are crossing varieties of the same species in ways they could cross naturally.For example,disease-resistant varieties of wheat have been crossed with highyield wheat to combine these