单选题To keep______, we must do more outdoor exercises.

单选题Psychologists take opposing views of how external rewards, from warm praise to cold cash, affect motivation and creativity. Behaviorists, who study the relation between actions and their consequences, argue that rewards can improve performance at work and school. Cognitive(认识派的)researchers, who study various aspects of mental life, maintain that rewards often destroy creativity by encouraging dependence on approval and gifts from others. The latter view has gained many supporters, especially among educators. But the careful use of small monetary(金钱的)rewards sparks creativity in grade-school children, suggesting that properly presented inducements(刺激)indeed aid inventiveness, according to a study in the June Journal of Personality and Social Psychology. "If kids know they're working for a reward and can focus on a relatively challenging task, they show the most creativity," says Robert Eisenhower of the University of Delaware in Newark. "But it's easy to kill creativity by giving rewards for poor performance of or creating too much anticipation for rewards. " A teacher who continually draws attention to rewards or who hands out high grades for ordinary achievement ends up with uninspired students, Eisenhower holds. As an example of the latter point, he notes growing efforts at major universities to tighten grading standards and restore failing grades. In earlier grades, the use of so-called taken economies, in which students handle challenging problems and receive performance-based points toward valued rewards, shows promise in raising effort and creativity, the Delaware psychologist claims.

单选题______ the lights off, we could not go on with the work.

单选题Only after the invention of computers, ______ a step further.

单选题As a young man, Tom used to ______ in the town, ______ to find a job for a few coins.[A] knocking about; waited[B] knocked down; waiting[C] knock about; waiting[D] knocked down; waited

单选题WhatdoesLindadobeforedinner?A.Shewashesthedishes.B.Shehelpshermotherwiththecooking.C.Shehelpshermotherwiththecookingandwashesthedishes.

单选题______ is true to say that a dog is man's best friend. A. That B. What . C. It

单选题Whatisthemanplanningtodo?

单选题More than three million years ago, our ancestors were already on the march, rising on two legs to search for food, seek greener lands and, above all, to grow in body and brain. Let's meet some of them: 1. Australopithecus afarensis They had ape-like faces and their brains were a third the size of modem humans' brains. They lived 3-3.9 million years ago. Fossils were found in Ethiopia in 1974. 2. Paranthropus boisei Covered with fur, they had strong arms and gorilla-like faces. They lived 1-2.5 million years ago. Fossils were found in Tanzania in 1959. 3. Homo habilis Homo habilis, which actually means "handy man", was the first species to make and use primitive stone tools. They lived 1.6-2.2 million years ago. Fossils were found in Tanzania in 1960. 4. Homo erectus With skeletons very similar to those of modern humans, they were probably the first to use fire. They lived 30,000-1.8 million years ago. Fossils have been found in Africa and Asia since 1893. 5. Homo heidelbergensis They were skilled hunters who used spears to kill animals. Their bodies were similar to ours, although more muscular and larger boned. They lived 200,000-500,000 years ago. Fossils have been found in Ethiopia, Germany, France and Spain since 1921. 6. Homo Neanderthal Their brains were at least as large as those of the average modem humans, while their smaller bodies helped them deal with cold climates. They lived 30,000-230,000 years ago. Fossils have been found in France and Iraq since 1856.

单选题If only we ______ a phone! I am tired of lining up outside the public phone box.

单选题

单选题There are______dressmakers in the U. S. than in European countries.

单选题Research has shown that excessive noise damages people"s hearing. In fact many young people now suffer from deafness from regularly going to discos where the level of noise is so high that they have to shout to make themselves heard. Unfortunately, in spite of modern technology, noise is very much part of our modern world planes flying overhead, traffic thundering along busy roads, television, portable radios, all produce noise to which we have become so accustomed that we hardly notice it. In fact people going on country holidays have been known to complain that it is too quiet. They actually miss the noise they are used to in their daily lives. The problem is that noise, though it does not necessarily cause deafness, causes anxiety and this can in the long run prove harmful. However, the decision about more or less noise cannot be left to the scientists alone. It is up to us to decide what kind of world we want to live in.

单选题New York: when the first jet struck World Trade Center at 8:48 a.m. on Tuesday, the people in 2 World Trade Center with a view of the instant damage across the divide had the clearest sense of what they, too, must do: get out fast. Katherine Hachinski, who had been knocked off her chair by the blast of heat exploding from the neighboring tower, was one of those. Despite her 70 years of age, Ms Hachinski, an architect working on the 91st floor of 2 World Trade Center, the south tower, went for the stairs. Twelve floors above her, Judy Wein, an executive (经理), screamed and set off too. But others up and down the 110 floors, many without clear views of the damage across the way and thus unclear about what was happening, were not so sure. And the 18 minutes before the next plane would hit were ticking off. Amid the uncertainty about what was the best thing to do, formal announcements inside the sound tower instructed people to stay put, assuring them that the building was sound and the threat was limited to the other tower. Some left, others stayed. Some began to climb down and, when met with more announcements and other cautions (警告) to stop or return. The decisions made in those instants proved to be of great importance, because many who chose to stay were doomed (注定死亡) when the second jet crashed into the south tower, killing many and stranding (使某物留在) many more in the floors above where the jet hit. One of those caught in indecision was the executive at Fuji Bank UAS. Richard Jacobs of Fuji Bank left the 79th floor with the other office workers, but on the 48th floor they heard the announcement that the situation was under control. Several got in the lifts and went back up, two minutes or so before the plane crashed into their floor. "I just don't know what happened to them," Mr. Jacobs said.

单选题While ______ in China, the young man picked up some Chinese.

单选题Whataretheytalkingabout?

单选题 American society does not treat nap friendly. In fact, says David Dinges, a sleep specialist (专家) at the University Of Pennsylvania School Of Medicine, "There's even a prohibition against admitting we need sleep". Nobody wants to be caught napping or found asleep at work. To quote a proverb: "Some sleep five hours, nature requires seven, laziness nine and wickedness eleven." "Wrong. The way not to fall asleep at work is to take naps when you need them. We have to totally change our attitude toward napping." says Dr. William Dement of Stanford University, the godfather of sleep research. Last year a national commission led by Dement identified an "American sleep debt" which one member said was as important as the national debt. The commission was concerned about the dangers of sleepiness: people causing industrial accidents or falling asleep while driving. This may be why we have a new sleep policy in the White House. According to recent reports, President Clinton is trying to take a half hour snooze (打盹) every afternoon. About 60 percent of American adults nap when given the opportunity. We seem to have "a mid-afternoon quiet phase" also called "a secondary sleep gate". Sleeping 15 minutes to two hours in the early afternoon can reduce stress and make us refreshed. Clearly, we were born to nap. We don't nap to replace shut-eye or to prepare for a night shift. Rather, we snack on sleep, whenever, wherever and at whatever time we feel like it. I myself have napped in buses, cars, planes and on boats, on floors and beds, and in libraries, offices and museums.