单选题I don't quite {{U}}follow{{/U}} what she is saying．

单选题Her treatment of the subject is {{U}}exhaustive{{/U}}. A. boring B. thorough C. interesting D. touching

单选题I was amazed at the beauty of the mountain when I reached the top.A. excitedB. astonishedC. happyD. shocked

单选题One-room schoolhouses can still be found in isolated areas of North America. A. bare B. deprived C. remote D. developed

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。 An international team of research scientists has created a new kind of rice that contains Vitamin A. The researchers used genetic engineering to create the new rice. Genetic engineering is the technology of changing the genes of living things. The researchers say the rice could help millions of people who do not get enough Vitamin A in the food they eat. The findings were published in Science magazine. Vitamin A is necessary for the body's natural defense system against disease. Vitamin A is needed to help prevent skin and other tissues from drying out. It also produces a light-sensitive substance in the eyes. People who do not get enough Vitamin A cannot see well in the dark. They may develop a condition that dries the eyes. The condition can result in infections that lead to blindness. A lack of Vitamin A is a major cause of blindness among children. Health experts estimate that 124 million children around the world do not eat enough foods with Vitamin A. Vitamin A is found in fish liver oil and in the yellow part of eggs. Vegetables such as carrots and sweet potatoes contain beta carotene, a substance that the body changes into Vitamin A. Public health campaigns to provide Vitamin A to those who need it have proved costly. And they are not always effective. That has led researchers to try to create foods with the vitamin. Rice is one of the most common crops grown worldwide. However, normal rice lacks Vitamin A. Researchers at a laboratory in Switzerland found a way to change the genetic material of rice. They added three genes to the rice. The genes produce beta carotene, the chemical that our bodies change into Vitamin A. The new rice has a golden yellow color. The researchers say 200 grams of the rice have enough beta carotene to provide the necessary amount of Vitamin A. Biologist Mary Lou Guerinot of Dartmouth College wrote a commentary published with the report in science magazine. She said the rice is an excellent example of the good things that can be done with genetic engineering. However, critics of genetic engineering argue that changing plant genes could increase risks to human health or the environment.

单选题The committee Ucomprises/U five persons.

单选题Disease, Diagnosis, Treatment and Prevention Disease may be defined as the abnormal state in which part or all of the body is not properly adjusted or is not capable of carrying on all its required functions. There are marked variations in the extent of the disease and in its effect on the person. In order to treat a disease, the doctor obviously must first determine the nature of the illness — that is, make a diagnosis. A diagnosis is the conclusion drawn from a number of facts put together. The doctor must know the symptoms, which are the changes in body function felt by the patient; and the signs (also called objective symptoms) which the doctor himself can observe. Sometimes a characteristic group of signs (or symptoms) accompanied a given disease. Such a group is called a syndrome. Frequently certain laboratory tests are performed and the results evaluated by the physician in making his diagnosis. Although nurses do not diagnose, they play an extremely valuable role in this process by observing closely for signs, encouraging the patient to talk about himself and his symptoms, and then reporting this information to the doctor. Once the patient's disorder is known, the doctor prescribes a course of treatment, also referred to as therapy. Many measures in this course of treatment are carried out by the nurse under the physician's orders. In recent years physicians, nurses and other health workers have taken on increasing responsibilities in prevention. Throughout most of medical history, the physician's aim has been to cure a patient of an existing disease. However, the modern concept of prevention seeks to stop disease before it actually happens — to keep people well through the promotion of health. A vast number of organizations exist for this purpose, ranging from the World Health Organization (WHO) on an international level down to local private and community health programs. A rapidly growing responsibility of the nursing profession is educating individual patients toward the maintenance of total health — physical and mental.

单选题What We Need in Our Diet The primary consideration in achieving a balanced diet is now how much or how little we eat, but what we eat. Basically we need carbohydrates, protein, fat, vitamins and minerals, together with regular but not excessive exercise. Carbohydrates are found in foods such as bread, potatoes and sugar. They are excellent energy products, but if eaten to excess may be largely converted to fat and a reduction in the amount of carbohydrates or "starchy: foods is one of the obvious ways to reduce weight, since most of us eat too much of them anyway. Protein, found in meat and cheese, is used for tissue building and in the developed countries most people eat about 110g daily, which is a good deal more than the recommended minimum of 70g a day. Animal fats, e. g. butter are also good sources of energy, but are sometimes held to caus increased cholesterol levels in the blood (which may lead to fatty deposits in the arteries) and are therefore best avoided by people suffering from certain forms of heart disease, vegetable fats being recommended as a substitue. Vitamins are another essential requirement for health. There are about forty known vitamins, but the most generally referred to are A, B, C, D and E, Deficiency of Vitamin A, found in carrots, rose - hips, etc. , is alleged (据称) to affect the vision and the skin and reduce resistance to infection. Vitamin C, present in nearly all fruit, particularly oranges and other citrus fruit, has come to be regarded as particularly effective in the prevention of cold and low energy states. Among the minerals we need, the most important are calcium, iron and iodinc (碘). Milk is one of the richest sources of calcium, which helps to build our bones and our teeth. Lack of iron in the blood produces anaemia anay children and others suffering from anaemic conditions are generally advised to increase their intake of iron, which: may be found in liver, lentils, molasses and dates among other foods.

单选题The girl is gazing at herself in the mirror.

单选题The use of the chemical may present a certain hazard to the laboratory workers.

单选题I have heard this tune before, but I don't know the words to the song.A. themeB. rhymeC. melodyD. lyric

单选题Late-Night Drinking Coffee lovers beware. Having a quick "pick-me-up" cup of coffee late in the day will play havoc with your sleep. As well as being a stimulant, caffeine interrupts the flow of melatonin, the brain hormone that sends people into a sleep. Melatonin levels normally start to rise about two hours before bedtime. Levels then peak between 2 a.m. and 4 a.m., before falling again. "It"s the neurohormone that controls our sleep and tells our body when to sleep and when to wake," says Manrice Ohayon of the Stanford Sleep Epidemiology Research Center at Stanford University in California. But researchers in Israel have found that caffeinated coffee halves the body"s levels of this sleep hormone. Lotan Shilo and a team at the Sapir Medical Center in Tel Aviv University found that six volunteers slept less well after a cup of caffeinated coffee than after drinking the same amount of decal. On average, subjects slept 336 minutes per night after drinking caffeinated coffee, compared with 415 minutes after decal. They also took half an hour to drop off—twice as long as usual—and jigged around in twice as much. In the second phase of the experiment, the researchers woke the volunteers every three hours and asked them to give a urine sample. Shilo measured concentrations of a breakdown product of melatonin. The results suggest that melatonin concentrations in caffeine drinkers were half those in decal drinkers. In a paper accepted for publication in Sleep Medicine , the researchers suggest that caffeine blocks production of the enzyme that drives melatonin production. Because it can take many hours to eliminate caffeine from the body, Ohayon recommends that coffee lovers switch to decal after lunch.

单选题The Case of the Disappearing Fingerprints One useful anti-cancer drug can effectively erase the whorls and other characteristic marks that give people their distinctive fingerprints. Losing 1 could become troublesome. A case released online in a letter by Annals of Oncology indicates bow big a 2 of losing fingerprints is. Eng-Huat Tan, a Singapore-based medical doctor describes a 62-year old man who has used capecitabine to 3 his nasopharyngeal cancer. After three years on the 4 , the patient decided to visit U.S. relatives last December. But be was stopped by U. S. customs officials 5 4 hours after entering the country when those officials couldn"t get fingerprints from the man. There were no distinctive swirly 6 appearing from his index finger. U.S. customs has been fingerprinting incoming foreign visitors for years, Tan says. Their index fingers are 7 and screened against digital files of the fingerprints of bad guys—terrorists and potential criminals that our federal guardians have been tasked with keeping out of the country. Unfortunately, for the Singaporean travelers, one potential 8 effect of his drug treatment is a smoothing of the tissue on the finger pads. 9 , no fingerprints. "It is uncertain when fingerprint loss will 10 to take place in patients who are taking capecitabine," Tan points out. So he cautions any physicians who 11 the drug to provide their patients with a doctor"s note pointing out that their medicine may cause fingerprints to disappear. Eventually, the Singapore traveler made it into the United States. I guess the name on his passport didn"t raise any red flags. But he"s also now got the explanatory doctor"s note—and won"t leave home 12 it. By the way, maybe the Food and Drug Administration, 13 approved use of the drug 11 years ago, should consider 14 its list of side effects associated with this medicine. The current list does note that patients may experience vomiting, stomach pain and some other side effects. But no where 15 it mention the potential for loss of fingerprints.

单选题The food is inadequate for ten people.

单选题Continuous short buzzes on the telephone indicate that the line is Ubusy/U after you dial the telephone number.

单选题"Wash every day and you'll die young, my son!" People often said those words; long ago, of course. Napoleon's wife had new clothes every month, instead of a bath. ("It's quicker," She always said). Rich people did not often have a bath. They washed their hands and faces, but not their bodies. Many poor people did not wash at all. A young man once said to a doctor; "Soap and water have never touched my body." (And the doctor answered. "That's true. I know... ") why didn't people wash in those days long ago? Well, they did not have water in their house. They carried water from rivers or from holes in the ground ( = wells). Towns people bought it from a water--carrier. Sometimes it was expensive; and soap was always expensive. They drank water, of course; and so they were clean inside. They did not think about the outside! And this is true; they just did not like a bath. Modern life is different. We use a lot of soap and water. And we are all quite clean. However, a few people use too much soap; and they often get ill. Who are these people? Many young women work as hairdressers. They wash and then "dress" other women's hair. That is their job, and they like it. Young hairdressers sometimes wash dirty heads on a busy day! Their hands are soapy for seven or eight hours; and that is not a good thing. A young hairdresser's hands are often red and ugly; and she must then go to doctor.

单选题A co - worker of mine recently recommended to do some research online before making my next purchase. As an elementary school teacher with a modest salary and a sizeable mortgage, cost was a major concern. While searching the Web I found a few online teeth whitening companies giving away free trials where you only had to pay a few dollars for shipping. I ordered two products, Dazzle White and Total White, both of which had 9/10 ratings and positive feedback from all users. After using the first product the results were noticeable, but after following with the second product I had a celebrity white smile. I'm far from a medical expert, but it appears that each product focused on DIFFERENT parts of the problem and that the second one put the whitening effect into overdrive. By using them both in a row I had absolutely unbelievable results. I can't believe companies are practically giving these products away! What is the economic status of the elementary school teacher?A. A not big salary with a great mortgage.B. Avery small salary to buy anything fancy.C. A not big salary with a moderate mortgage.D. A good salary with a great mortgag

单选题The unemployment rate may rise {{U}}slightly{{/U}}.

单选题Older Volcanic Eruptions Volcanoes were more destructive in ancient history, not because they were bigger, but because the carbon dioxide they released wiped out life with greater ease. Paul Wignall from the University of Leeds was investigating the link between volcanic eruptions and mass extinctions. Not all volcanic eruptions killed off large numbers of animals, but all the mass extinctions over the past 300 million years coincided with huge formations of volcanic rock. To his surprise, the older the massive volcanic eruptions were, the more damage they seemed to do. He calculated the "killing efficiency" for these volcanoes by comparing the proportion of life they killed off with the volume of lava that they produced. He found that size for size, older eruptions were at least 10 times as effective at wiping out life as their more recent rivals. The Permian extinction, for example, which happened 250 million years ago, is marked by floods of volcanic rock in Siberia that cover an area roughly the size of western Europe. Those volcanoes are thought to have pumped out about 10 gigatonnes of carbon as carbon dioxide. The global warming that followed wiped out 80 percent of all marine genera at the time, and it took 5 million years for the planet to recover. Yet 60 million years ago, there was another huge amount of volcanic activity and global warming but no mass extinction. Some animals did disappear but things returned to normal within ten thousands of years. "The most recent ones hardly have an effect at all," Wignall says. He ignored the extinction which wiped out the dinosaurs 65 million years ago, because many scientists believe it was primarily caused by the impact of an asteroid. He thinks that older volcanoes had more killing power—because more recent life forms were better adapted to dealing with increased levels of CO 2 . Vincent Courtillot, director of the Paris Geophysical Institute in France, says that Wignall"s idea is provocative. But he says it is incredibly hard to do these sorts of calculations. He points out that the killing power of volcanic eruptions depends on how long they lasted. And it is impossible to tell whether the huge blasts lasted for thousands or millions of years. He also adds that it is difficult to estimate how much lava prehistoric volcanoes produced, and that lava volume may not necessarily correspond to carbon dioxide emissions.

单选题Some people would like to do shopping on Sundays since they expect to pick up wonderful articles in the market.