Helicobacter pylori is one of humanity’s oldest and closest companions, and yet it took scientists more than a century to recognize it. As early as 1875, German anatomists found spiral bacteria colonizing the mucus layer of the human stomach, but because the organisms could not be grown in a pure culture, the results were ignored and then forgotten. It was not until 1982 that Australian doctors Barry J. Marshall and J. Robin Warren isolated the bacteria, allowing investigations of H pylori’s role in the stomach to begin in earnest. Over the next decade researchers discovered that people carrying the organisms had an increased risk of developing peptic ulcers—breaks in the lining of the stomach or duodenum—and that H pylori could also trigger the onset of the most common form of stomach cancer.Just as scientists were learning the importance of H pylori, however, they discovered that the bacteria are losing their foothold in the human digestive tract. Whereas nearly all adults in the developing would still carry the organism, its prevalence is much lower in developed countries such as the U.S. Epidemiologists believe that H pylori has been disappearing from developed nations for the past 100 years thanks to improved hygiene, which blocks the transmission of the bacteria, and to the widespread use of antibiotics. As H pylori has retreated, the rates of peptic ulcers and stomach cancer have dropped. But at the same time, diseases of the esophagus — including acid reflux disease and a particularly deadly type of esophageal cancer—have increased dramatically, and a wide body of evidence indicates that the rise of these illnesses is also related to the disappearance of H pylori.

1. The author’s primary purpose in writing this passage is to( ).

2.Which of the following statements can be inferred from the passage?

3.Which of the following would most probably follow the last sentence of this passage?

A.alter people to the harm of H pylori colonization of the stomach B.make people aware of the harm of eradicating H pylori from the stomach C.suggest that the benefits of eradicating H pylori from the stomach are not outweighed by the potential harm. D.call attention to the consequences of eradicating H pylori from the stomach.问题2： A.Improvements in sanitation are a vital element in helping ward off peptic ulcers. B.People in the developing countries are not likely to contract esophageal diseases. C.Nowadays few people in the developed countries suffer from stomach cancer. D.Scientists have long recognized H pylori’s important role in the stomach, but could do nothing about.问题3： A.Furthermore, the disappearance of H pylori may be a sentinel indicating the possibility of other microbial extinctions as well. B.The possibility that this bacterium may actually protect people against disease of the esophagus has significant implications. C.However, there has been an unexpected rise in the incidence of a new class of diseases involving the esophagus. D.The rise of these diseases has occurred just as H pylori has been disappearing, and it is tempting to associate the two phenomena.

The contribution genes make to intelligence increases as children grow older. This goes against thenotion that most people hold that as we age，environmental influences gradually overpower the geneticlegacy we are bom with and may have implications for education. “People assume the genetic influencegoes down with age because the environmental differences between people pile up in life,”says RobertPlomin. “What we found was quite amazing, and goes in the other direction.”Previous studies have shown variations in intelligence are at least partly due to genetics. To find out whether this genetic contribution varies with age, Plomin’s team pooled data from six separate studies carried out in the US, the UK, Australia and the Netherlands, involving a total of 11,000 pairs of twins. In these studies, the researchers tested twins on reasoning, logic and arithmetics to measure a quantity called general cognitive ability, or “G”. Each study also included both identical twins, with the same genes, and fraternal twins, sharing about half their genes, making it possible to distinguish the contributions of genes and environment to their G scores.Plomin’s team calculated that in childhood, genes account for about 41 percent of the variation inintelligence. In adolescence, this rose to 55 percent； by young adolescence, it was 66 percent. No one knows why the influence from genes should increase with age, but Plomin suggests that as children getolder，they become better at exploiting and manipulating their environment to suit their genetic needs,and says “ Kids with high G will use their environment to foster their cognitive ability and choose friendswho are like-minded. ” Children with medium to low G may choose less challenging pastimes andactivities, further emphasizing their genetic legacy.Is there any way to interfere with the pattern? Perhaps. “The evidence of strong heritability doesn’tmean at all that there is nothing you can do about it，” says Susanne Jaeggi，“From our own work, theones that started off with lower IQ scores had higher gains after training. ’’Plomin suggests that genetic differences may be more emphasized if all children share an identical curriculum instead of it being tailored to children’s natural abilities. “My inclination would be to give everyone a good education, but put more effort into the lower end,” he says. Intelligence researcher Paul Thompson agrees: “It shows that educators need to steer kids towards things drawing out their natural talents.”

1.What is the common notion that people hold about genes?2.The study by Plomin’s team aims to find out ( )3.From the experiment with twins, Plomin’s team draws a conclusion that( ) .

4.The word “pattern” in paragraph four is closest in meaning to( ) .

5.Which of the following might Plomin’s team least agree to?

A.Humans can do little to change the genetic differences between people. B.Genetic influence becomes stronger when people receive education. C.Genes contribute more to one’s intelligence than environmental factors. D.Environmental factors lessen the influence of genes on one’s intelligence.问题2： A.whether variations in intelligence are caused by genetic differences B.how to overpower genetic factors with new educational approaches C.whether genetic contribution to one’s intelligence varies with age D.the relationship between environment and genes问题3： A.genetic contribution increases when one grows older B.genetic influence decreases when age increases C.environment has more impact on fraternal twins than identical twins D.it remains a mystery how genes and environment co-influence people问题4： A.cognitive ability B.strong heritability C.genetic legacy D.challenging pastimes问题5： A.An identical curriculum to school children. B.A differentiated course design to children with varied IQ. C.More effort directed at children with medium or low G. D.Education tailored to children’s natural abilities.

Every time a person eats something he makes a nutritional decision. He accepts or rejects the food available to him at home for meals or snacks. Or he selects food for himself at many places in the community, such as supermarkets, drive-ins, restaurants, and food counters in drugstores. These selections make a difference in how an individual looks, how he feels, and how well he can work and play.When a good assortment of food in appropriate amounts is selected and eaten, the consequences are more likely to be a desirable level of health and enough energy to allow one to be as active as one needs and wants to be. When choices are less than desirable, the consequences are likely to be poor health or limited energy or both.Studies of diets of individuals in the United States show that food selection is a highly individual matter, even among young children. Furthermore, far too many individuals of all ages are making poor choices day after day and are either now living with the consequences or will be in the future.Nutritionists and workers in allied professions have been concerned about helping people learn to select and enjoy a wide variety of food combinations that can add up to a good diet.Most people believe that they are well fed—that the choices they make are good ones. After all, they are not really sick, neither are they hungry. However, their nutrition is usually poor in one respect or another. Milk and milk products, such as cheeses, ice cream or milk, buttermilk, and yogurt, are often slighted. Then people may skip many fruits and vegetables, particularly those that are good sources of vitamins A and C.These include dark green leafy vegetables; deep yellow vegetables; and citrus fruits and vegetables, such as cabbage, tomatoes, and green peppers.Every American has the right to choose to be uniformed about nutrition as well as to be informed. If a person believes that she is well fed, attitudes, habits, and information cannot be forced upon her.There are life situations, however, that tend to cause all individual to want to know how to make the best choices. For example, a young couple is starting a family and must prepare food for young children.

1.Food preference in America is ______.2.Good amounts of vitamin A can be found in ______.3.According to the author, nutritionists are concerned with ______.4.Some people judge their nutrition by the ______.5.The author advocates______.

A.culturally oriented B.inherited C.individualistic D.according to ages问题2： A.celery B.banana C.milk D.cabbage问题3： A.improving the vitamin content of processed foods B.restricting the manufacture of high cholesterol foods C.informing the public about wholesome foods D.helping people enjoying uninformed about nutrition问题4： A.status of their health B.grocery stores where they shop C.amount of protein in their diets D.food they took问题5： A.requiring high school students to take courses on nutrition B.making information on nutrition available to the public C.forcing food manufacturers to list ingredients on packages D.people has the right to choose food

Traditional fairytales are being ditched by parents because they are too （ ）for their young children, a study found.

A.scarce B.scary C.scared D.scarred

The federal court has been putting pressure on the state to adhere to the population caps in the decree.

A.encounter B.stick to C.prepare D.anticipate

Human choice, not the intrinsic content of science, determines the outcome and scientists, as human beings, therefore have a special responsibility to provide council rooted in（ ）.

A.expiration B.explanation C.expertise D.expenditure