单选题Unfortunately, only half of the villagers ______ the snow slide last night.

单选题One motion is adopted by the Security Council only if ______.

单选题What does the sentence "The bulging centres will increasingly become fertile fields for social unrest" mean?

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单选题Scientists are responsible for people who hold harmful beliefs about human nature because.

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单选题As a volunteer, John Apollos is losing weight—the old-fashioned way—by eating less. Apollos has lowered his daily caloric intake 25% over the past eight months. The fat, not surprisingly, has melted away. But that"s not the real reason Apollos and the other participants in the program are eating only three-quarters of what they used to. The researchers are trying to determine whether restricting food intake can slow the ageing process and extend our life span. "I feel better and lighter and healthier," says Apollos. "But if it could help you live longer, that would be pretty amazing." The idea is counterintuitive: If we eat to live, how can starving ourselves add years to our lives? Yet decades of calorie-restriction studies involving organisms ranging from microscopic yeast to rats have shown just that. Last July a long-term study led by researchers at the University of Wisconsin, found that calorie restriction seemed to extend the lives of humanlike rhesus monkeys (恒河猴) as well. The hungry primates fell victim to diabetes, heart and brain disease and cancer much less frequently than their well-fed counterparts did. Scientists have suspected that calorie restriction could extend the life span of animals since at least 1935, when researchers at Cornell University noticed that severely food-restricted lab rats lived twice as long as normal ones and were healthier. Other investigators began exploring the idea and learned that the secret is not merely a matter of body weight. One theory is that a state of slight hunger acts as a mild but constant stressor that makes an organism stronger and more resistant to the ills of ageing. Taking in fewer calories also slows metabolism (新陈代谢), and some data indicate that humans with a slower metabolism live longer. But even if these theories are correct, simply defining the mechanism is not the same as identifying the molecular pathways behind it. If researchers could determine those pathways, they might be able to pharmacologically mimic (模仿) the effect of calorie restriction. That could be the ultimate benefit of the CALORIE study. "Calorie restriction is pretty much the only thing out there that we know will not just prevent disease but also extend maximal life span," says Dr. Marc Hellerstein, a nutritionist at the University of California.

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单选题According to the last paragraph, consumers who believe that organic foods are better than conventionally grown foods are often

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单选题To make matter worse, dirty jeans are the ideal place for germs, which ________ poor health.

单选题 BQuestions 11 to 18 are based on the conversation you have just heard./B

单选题Mobile office is the mutual product of economic, scientific and social progress. Mobile office has become a solution that provided users with convenient, prompt, safe, reliable and reasonably priced communications and office faculty anywhere anytime via the support of mobile interconnection platform (MIP) and its applications systems. When you leave your office to attend meetings or travel on business, what would happen to your business routine? of course, faxes and e-mails would be still sent to your fax machine or e-mail box, but you cannot read them and make prompt reaction timely. When your clients need you to make some urgent modifications on your work and you are neither in the office nor carrying relevant documents, what can you do? Maybe you have to say "sorry" to the clients. But, your business will be affected, the clients will be unhappy and disappointed because of your delay, and you will lose a lot of business opportunities. In fact, very frequently, you need to check, reply, distribute, display, modify or read some materials when you are not in your office. You must get out of this dilemma. The best solution to normally handle your business anywhere anytime and not to disappoint your clients is to let your office "move" with you. Thus, you can have convenient, prompt, safe, reliable and reasonably priced communications and office faculty anywhere anytime. With the development of communications technology, network application and wireless interconnection, mobile office has become simpler and smaller, and even can be realized via one mobile phone with data communications function. Thus, mobile office has already been put into your pocket, and office mobility has been realized. Mobile office has provided people with convenient, casual working environment, but at the same time it still has some unsatisfactory aspects such as mismatching equipment interface and inadequate battery. Nevertheless, we believe that with technical progress, people can certainly overcome all kinds of difficulties. Mobile office will make your career successful, and will realize the dream of completely free communication. Users will enjoy more colorful life and better working environment, and users' living standard, working efficiency and even enterprises' production efficiency will certainly be immensely raised.

单选题According to the passage, it is generally believed that ______.