题目

用如下图所示装置来测定空气中氧气的含量，对该实验认识错误的是（） A . 铜粉用量的多少，会影响实验结果 B . 实验结束后冷却到室温才能读数 C . 气球的作用是调节气压，使氧气完全反应 D . 在正常操作情况下，反应后消耗氧气的体积应该是反应前注射器内气体体积的1/5 答案：DHave you ever been stuck(困住) for hours on a hard math problem? If you sat there for some time you might eventually solve it, but scientists say that daydreaming might be a much better way to tackle(处理) difficult tasks.In fact, daydreaming has long been misunderstood. It’s considered to be a bad thing and often associated with laziness. “We’re harsh(严厉的) on ourselves if we catch ourselves mind wandering,” says Professor Kalina Christoff from the University of British Columbia in Canada.But the truth is that some of the most important scientific discoveries came about because scientists allowed their minds to wander. For example, Albert Einstein began his theory of relativity(相对论) when he daydreamed about riding a beam(束) of sunlight to the edge of the universe. And now, research has shown that normal people can also improve their problems solving ability in the same way, reported The Telegraph.In a study, 145 people aged between 19 and 32 were asked to list as many unusual uses as possible for everyday objects. Some of them were given a 12-minute break while the others were not allowed any break from the task. People on the break did not simply relax—some of them were told to carry out a tiring memory task while others did an easier task.Scientists found that people who did the easier task were daydreaming a lot. They thought about personal issues in the past or in the future because their mind was at ease.After the break, all participants were asked to return once again to the task of listing unusual uses for everyday objects. It was found that daydreamers improved their performance by 40 percent, while all the other people, including those who didn’t have a break and who did tiring tasks during the break, performed the same as before.“People think that when the mind wanders away, it just gets turned off—but we show the opposite,” explained Christoff. “A more playful attitude might allow you to call in more resources(解决办法).” So when you are struggling to solve complicated problems, it might be better off if you switch to a simpler task and let your mind wander for a while, she sug­gested.According to Christoff, people typically spend one-third of their waking time daydreaming. “It’s a big part of our lives, but it’s been largely ignored(忽视) by science.”1.. It was believed that daydreaming __________.A. had something to do with imaginationB. had been misunderstood for a long timeC. was a waste of time when the mind was shut offD. was a good way to relax and solve problems2.. What is the main purpose of Paragraph 3?A. To show that great scientists daydream a lot.B. To inform us that daydreaming has its benefits.C. To prove people can daydream whenever they like.D. To introduce new experiments on daydreaming.3.. What did the scientists discover in the experiment?A. People’s minds turned off as they daydreamed.B. The group that were given hard memory tasks performed best.C. People who had a break showed improvement in the task.D. Daydreaming could improve people’s problem-solving abilities.4.. How did the scientists get their conclusion?A. By studying brain scan results of the groups.B. By comparing the performances of different groups.C. By asking and observing people in different groups.D. By analyzing the amount of tasks each participant did.