A man living absolutely alone in a desert or forest is free from other people; but he is not absolutely free. His freedom is limited in several ways. Firstly, by the things around him, such as wild animals or cliffs too steep   to climb. Secondly, by his own needs: he must have sleep, water, food and shelter from extreme heat or cold. Lastly, by his own nature as a man: disease may attack him, and death will certainly come to him sooner or later. When men live together, on the other hand, protection against wild animals is easier and they can work together to get food and build shelters; but each man has to give up some of his freedom so that he can live happily with the others. When men become organized into very large groups, and civilization   develops, it is possible to get freedom from hunger, thirst, cold, heat and many diseases, so that each person can live a happier life than he could if he were living alone; but such a society can not work successfully unless the freedom of each human being is to some extent limited so that he is kept from hurting others. I am not free to kill others, nor to steal someone else's property, nor to behave in a way that offends   against the moral sense of the society in which I live. I have to limit my own freedom myself so that others will not limit it too much: I agree to respect the rights of others, and in return they agree to respect mine. The advantages of such an agreement are great: one man can become a doctor, knowing that others will grow food, make clothes and build a house for him, in return for the work he does to keep them healthy. If each man had to grow his own food, make his own clothes, build his own house and learn to be his own doctor, he would find it impossible to do any one of these jobs really well. By working together, we make it possible for society to provide us all with food, clothes, shelter and medical care, while leaving each of us with as much freedom as it can. A man living alone in a desert or forest    _   . A) is completely free B) feels rather lonely C) has limited freedom D) enjoys no freedom
C
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Why do human beings still risk their lives under ground and doing one of the dirtiest and most dangerous jobs in the world? It's an increasingly urgent question, given the recent mining accidents in Sago. W. Va. and Huntington, Utah. A small group of engineers and robotics experts look forward to a day in the not-too-distant future when robots and other technology do most of the dangerous mining work. Robotic technology, in particular, holds much promise, McAteer says, especially when it comes to mapping mines and rescuing trapped miners--the special operations of the mining industry. One of the first mining robots was developed five years ago at Canegie-Mellon University's Robotics Institute. It was called Groundhog. It used lasers to "see" in dark tunnels and map abandoned mines - some of the most dangerous work in the business The latest design is called Cave Crawler. It's a bit smaller than Grondhog, and even more advanced. It can take photos and video and has more sensors that can discover the presence of dangerous gases. The robot has a real sense of logic, which is hard to believe. If it comes across a thing in the way it gets confused. It has to think through the process and where to go next, and sometimes it _ just like a real person. The greatest problem, though, is cost. The money of the earliest research project was provided by the government, but that money has dried up, and it's not clear where future money will come from. Partly for that reason, and partly because of advances in safely, mining is not nearly as dangerous as it was in the past. Since 1990,fatalities  have declined by 67 percent and injuries by 51 percent, according to the National Mining Association. Some experts predict that robots in the mines will serve much of the same function that they do in the automotive industry. The robot do the most boring and dangerous jobs, but don't eliminate the need for human workers. What can be the best title for the text? A) Mining Accidents in America B) Robots in Mines C) Cave Crawler, the Latest Robot D) The Future of Robots
B
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A robot is a computer-controlled machine that is programmed to move and handle objects. Robots are able to perform repetitive tasks more quickly, cheaply, and accurately   than humans. In 1995, about 700,000 robots were used-including over 500,000 in Japan, about 120,000 in Western Europe, and about 60,000 in the United States-all in the industrialized world. Many robots applications are designed for tasks that are either dangerous or unpleasant for human beings. Now, robotic technology can be used in more and more fields. Experts say in the future robots will be able to make new highways, constructsteel frameworks of buildings, clean sewage  , and such physical work. Besides, another possibility is the development of robotic technology in medical surgery operations. Perhaps the greatest changes in future robots will improve from their increasing ability to reason. The field of artificial intelligence is moving rapidly from university labs to practical application in industry, and machines of a new kind of robots are being developed, _ can perform something involved in the process of understanding and planning, such as the management of a battlefield. Even the control of a large factory will be performed by intelligent computers. And there might be a possibility that these computers can design and make robots of their own. Is there anything dangerous involved in this artificial intelligence progress then? Robot technology has been making people nervous ever since it was invented. Is it unreasonable to worry that robots will someday become too clever? Is it impossible that these human-like robots will start to think and plan for themselves? Will robots take over the world and force humans to give them energy to survive? Which of the following do experts say robots won't be able to do in the future? A) Take care of roads. B) Be used as medicine. C) Used as underground pipeline cleaner. D) Take up jobs of building construction.
B
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Want to be a happy married couple? Consider having kids. A new study found that having children boosts happiness.And the more, literally, the merrier. But unmarried couples shouldn't expect to find greater happiness through child-raising.The study, published in the Oct.14 online edition of the Journal of Happiness Studies, suggests that having children has little or no effect on boosting happiness among couples who aren't hitched . The findings contradict previous research that suggested that having more offspring doesn't lead to greater happiness and might even make people less satisfied with their lives.One theory behind the conclusion is that parents don't receive many rewards in return for the hard work of raising children. The new study, however, notes that parents say children are one of the most important things in their lives, if not the most important. The study found that life satisfaction for married people -- women especially -- goes up the more kids they have.Single, separated and co-habiting people, by contrast, report negative experiences. "One is tempted to advance that children make people rich under the 'right conditions' -- a time in life when people feel that they are ready, or at least willing, to enter parenthood," Dr.Luis Angeles, of the University of Glasgow in Scotland, said in a news release from the journal's publisher."This time can come at very different moments for different individuals, but a likely signal of its approach may well be the act of marriage." Which of the following can be inferred from the passage? A) The more children women have, the happier they are. B) The more children the married women have, the more unsatisfied they become. C) Raising kids can give any person happiness. D) Without marriage, one woman had better not raise kids.

D
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