B There have always been a lot of commonly believed but false ideas about being fat and doing exercise. Some people believe that they can’t help putting on weight as they get older, while others hold that if they stop exercising, their muscles will turn into fat. Here are some more myths: I’ll never lose weight --- I come from a fat family Wrong! While we can’t change the body type we are born with, we can’t blame our genes for making us fat. There’s plenty of evidence that fatness runs in families, and the main reason is that they share the same habits of eating too much and exercise too little. I am fat because I burn calories slowly Wrong! Fatness is not caused by a slow metabolism（新陈代谢）. If fact, although fat people consume more energy that slim people, they also fail to realize how much they eat! Keeping a diary can help you work out your daily food intake more accurately. Exercise is boring Wrong! Anything will become boring if you do it repetitively. The key is to develop a balanced and varied program that’s fun as well as progressive. If you enjoy a Sunday walk, take a different route. If you do Yoga, try a tai chi class. If you like swimming, set yourself a distance or time challenge. No pain, no gain Wrong! Exercise is not meant to hurt. Indeed, pain is your body telling you something’s wrong, and continuing to exercise could lead to serious injury. You may experience mild discomfort as you begin to exercise regularly, but this your body adapting to the positive changes in your lifestyle and the aches should disappear relatively quickly. If you don’t, rest and seek medical advice. What is the purpose of the passage

A:To declare the importance of keeping fit. B:To clarify some misconceptions about fatness and exercise. C:To confirm what has long been believed about keeping fit. D:To explain some medical facts about being fat and doing exercise.

One of the most important social developments that helped to make possible a shift in thinking about the r01e of public education was the effect of the baby boom of the 1950s and 1960s on the schools. In the 1920s, but especially in the Depression conditions of the 1930s, the United States experienced a declining birth rate—every thousand women aged fifteen to forty-four gave birth to about 118 live children in 1920, 89.2 in 1930, 75.8 in 1936, and 80 in 1940. With the growing prosperity brought on by the Second World War and the economic boom that followed it, young people married and established households earlier and began to raise larger families than had their predecessors during the Depression. Birth rates rose to 102 per thousand in 1946, 106.2 in 1950, and 118 in 1955. Although economics was probably the most important determinant, it is not the only explanation for the baby boom. The increased value placed on the idea of the family also helps to explain this rise in birth rates.
The baby boomers began streaming into the first grade by the mid-1940s and became a flood by 1950. The public school system suddenly found itself overtaxed. While the number of schoolchildren rose because of wartime and postwar conditions, these same conditions made the schools even less prepared to cope with the flood. The wartime economy meant that few new schools were built between 1940 and 1945. Moreover, during the war and in the boom times that followed, large numbers of teachers left their profession for better-paying jobs elsewhere in the economy.
Therefore, in the 1950s and 1960s, the baby boom hit an antiquated and inadequate school system. Consequently, the "custodial rhetoric" of the 1930s and early 1940s no longer made sense; that is, keeping youths aged sixteen and older out of the labor market by keeping them in school could no longer be a high priority for an institution unable to find space and staff to teach younger children aged five to sixteen.
With the baby boom, the focus of educators and of laymen interested in education inevitably turned toward the lower grades and back to basic academic skills and discipline. The system no longer had much interest in offering nontraditional, new, and extra services to older youth.
The "custodial rhetoric" mentioned in Paragraph 3 refers to______.

A:raising a family B:keeping older individuals in school C:running an orderly household D:maintaining discipline in the classroom

One of the most important social developments that helped to make possible a shift in thinking about the r01e of public education was the effect of the baby boom of the 1950s and 1960s on the schools. In the 1920s, but especially in the Depression conditions of the 1930s, the United States experienced a declining birth rate—every thousand women aged fifteen to forty-four gave birth to about 118 live children in 1920, 89.2 in 1930, 75.8 in 1936, and 80 in 1940. With the growing prosperity brought on by the Second World War and the economic boom that followed it, young people married and established households earlier and began to raise larger families than had their predecessors during the Depression. Birth rates rose to 102 per thousand in 1946, 106.2 in 1950, and 118 in 1955. Although economics was probably the most important determinant, it is not the only explanation for the baby boom. The increased value placed on the idea of the family also helps to explain this rise in birth rates.
The baby boomers began streaming into the first grade by the mid-1940s and became a flood by 1950. The public school system suddenly found itself overtaxed. While the number of schoolchildren rose because of wartime and postwar conditions, these same conditions made the schools even less prepared to cope with the flood. The wartime economy meant that few new schools were built between 1940 and 1945. Moreover, during the war and in the boom times that followed, large numbers of teachers left their profession for better-paying jobs elsewhere in the economy.
Therefore, in the 1950s and 1960s, the baby boom hit an antiquated and inadequate school system. Consequently, the "custodial rhetoric" of the 1930s and early 1940s no longer made sense; that is, keeping youths aged sixteen and older out of the labor market by keeping them in school could no longer be a high priority for an institution unable to find space and staff to teach younger children aged five to sixteen.
With the baby boom, the focus of educators and of laymen interested in education inevitably turned toward the lower grades and back to basic academic skills and discipline. The system no longer had much interest in offering nontraditional, new, and extra services to older youth.

The "custodial rhetoric" mentioned in Paragraph 3 refers to（）

A:raising a family B:keeping older individuals in school C:running an orderly household D:maintaining discipline in the classroom

Doctors say anger can be an extremely damaging emotion, unless you learn how to deal with it . They warn that angry hostile feelings can lead to heart disease, stomach problems, headaches, emotional problems and possible cancer.
Anger is a normal emotion that we all feel from time to time. Some people express anger openly in a calm reasonable way. Others explode with anger, and yell. But other people keep their anger inside. They can not or will not express it. This is called repressing(压制) anger.
For years many doctors thought that compared with expressing anger, repressing anger was more dangerous to a person’s health. It may speed the heart rate, raise blood pressure or sugar into the blood and narrow the blood vessels. To avoid these problems, doctors thought a person should let the anger out by expressing it freely. But recently some doctors disputed this. They said that people who express anger repeatedly and explosively did cause, in fact, more and not less anger. They said these too can cause medical problems.
Some doctors say that both repressing and expressing anger can be dangerous. Expressing anger intensively may be more likely to develop heart disease, and keeping anger inside may face a greater danger of high blood pressure. Doctors say the solution is learning how to deal with anger. They say the first step is to admit that you are angry and to recognize the real cause of the anger, then decide if the cause is serious enough to get angry about. If it isn’t, they say, " Don’t express your anger while angry. Wait until your anger has cooled down and you are able to express yourself calmly and reasonably. "
Doctors say that a good way to deal with anger is to find humor in the situation that has made you angry. They said that laughter is much healthier than anger.
It can be concluded from the passage that ______.

A:keeping anger inside is better than expressing it intensively B:both repressing and expressing anger cause health problems C:keeping anger inside is more likely to cause heart disease D:expressing anger freely can avoid medical problems

Using enzymes commonly found in living cells, a new type of fuel cell produces small amounts of electricity from sugar. If the technology is able to succeed in mass production, you may some day share your sweet drinks with your cell phone.
In fuel cells, chemical reactions generate electrical currents. The process usually relies on precious metals, such as platinum. In living cells, enzymes perform a similar job, breaking down sugars to obtain electrons and produce energy.
When researchers previously used enzymes in fuel cells, they had trouble keeping them active, says Shelley D. Minteer of St Louis University. Whereas biological cells continually produce fresh enzymes, there’s no mechanism in fuel cells to replace enzymes as they quickly degrade.
Minteer and Tamara Klotzbach, also of St Louis University, have now developed polymers that wrap around an enzyme and preserve it in a microscopic pocket. "We tailor these pockets to provide the ideal microenvironment" for the enzyme, Minteer says. The polymers keep the enzyme active for months instead of days.
In the new fuel cell, tiny polymer bags of enzyme are embedded in a membrane that coats one of the electrodes. When glucose from a sugary liquid gets into a pocket, the enzyme oxidizes it, releasing electrons and protons. The electrons cross the membrane and enter a wire through which they travel to the other electrode, where they react with oxygen in the atmosphere to produce water. The flow of electrons through the wire constitutes an electrical current that can generate power.
So far, the new fuel cells don’t produce much power, but the fact that they work at all is exciting, says Paul Kenis, a chemical engineer at the University of Illinois at Urhana-Champaign. "Just getting it to work," Kenis says, "is a major accomplishment."
Sugar-eating fuel cells could be an efficient way to make electricity. Sugar is easy to find. And the new fuel cells that run on it are biodegradable, so the technology wouldn’t hurt the environment. The scientists are now trying to use different enzymes that will get more power from sugar. They predict that popular products may be using the new technology in as little as 3 years.
What trouble did Minteer and Klotzhach have in their research

A:They had trouble keeping enzymes in fuel cells active. B:They had trouble keeping biological cells active. C:They had trouble producing fresh enzymes. D:They had trouble finding mechanism for producing enzymes.

Using enzymes commonly found in living cells, a new type of fuel cell produces small amounts of electricity from sugar. If the technology is able to succeed in mass production, you may some day share your sweet drinks with your cell phone.
In fuel cells, chemical reactions generate electrical currents. The process usually relies on precious metals, such as platinum. In living cells, enzymes perform a similar job, breaking down sugars to obtain electrons and produce energy.
When researchers previously used enzymes in fuel cells, they had trouble keeping them active, says Shelley D. Minteer of St Louis University. Whereas biological cells continually produce fresh enzymes, there’s no mechanism in fuel cells to replace enzymes as they quickly degrade.
Minteer and Tamara Klotzbach, also of St Louis University, have now developed polymers that wrap around an enzyme and preserve it in a microscopic pocket. "We tailor these pockets to provide the ideal microenvironment" for the enzyme, Minteer says. The polymers keep the enzyme active for months instead of days.
In the new fuel cell, tiny polymer bags of enzyme are embedded in a membrane that coats one of the electrodes. When glucose from a sugary liquid gets into a pocket, the enzyme oxidizes it, releasing electrons and protons. The electrons cross the membrane and enter a wire through which they travel to the other electrode, where they react with oxygen in the atmosphere to produce water. The flow of electrons through the wire constitutes an electrical current that can generate power.
So far, the new fuel cells don’t produce much power, but the fact that they work at all is exciting, says Paul Kenis, a chemical engineer at the University of Illinois at Urbana-Champaign. "Just getting it to work," Kenis says, "is a major accomplishment. /
What trouble did Minteer and Klotzbach have in their research

A:They had trouble keeping enzymes in fuel cells active. B:They had trouble keeping biological cells active. C:They had trouble producing fresh enzymes. D:They had trouble finding mechanism for producing enzymes.

下面有3篇短文，每篇短文后有5道题，每题后面有4个选项。请仔细阅读短文并根据短文回答其后面的问题，从4个选项中选择1个最佳答案。
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What trouble did Minteer and Klotzbach have in their research?

A:They had trouble keeping enzymes in fuel cells active. B:They had trouble keeping biological cells active. C:They had trouble producing fresh enzymes. D:They had trouble finding mechanism for producing enzymes.