单选题{{B}}练习十三{{/B}} Is the outcome in a monopolistically (垄断地) competitive market desirable from the standpoint of society as a whole? Can policymakers improve on the market outcome? There are no simple answers to these questions. One source of inefficiency is the markup (涨价) of price over marginal cost. Because of the markup, some consumers who value the good at more than the marginal cost of production (but less than the price) will be deterred (被阻止) from buying it. Thus, a monopolistically competitive market has the normal deadweight loss of monopoly .pricing. Although tins outcome is clearly undesirable compared to the first-best outcome of price equal to marginal cost, there is no easy way for policymakers to-fix the problem. To enforce marginal-cost pricing, policymakers would need to regulate all firms that produce differentiated products. Because such products are so common in the economy, the administrative burden of such regulation would be overwhelming. Moreover, the regulating monopolistic competitors would entail all the problems of regulating natural monopolies. In particular, because monopolistic competitors are making zero profits already, requiring them to lower their prices to equal marginal cost would cause them to make losses. To keep these firms in business, the government would need to help them cover these losses. Rather than raising taxes to pay for these subsidies, policymakers may decide it is better to live with tile inefficiency of monopolistic pricing Another way in which monopolistic competition may be socially inefficient is that the number of firms in the market may not be the "ideal" one. That is, there may be too much or too little entry. One way to think about this problem is in terms of the externalities associated with entry. Whenever a new firm considers entering the market with a new product, it considers only the profit it would make. Yet its entry would also have two external effects: a) The product-variety externality: Because consumers get some consumer surplus from the introduction of a new product, there is a positive externality associated with entry b) The business-stealing externality: Because other firms lose customers and profits from the entry of a new competitor, there is a negative externality associated with entry. Thus in a monopolistically competitive market, there are both positive and negative externalities associated with the entry of new firms. Depending on which externality is larger, a monopolistically competitive market could have either too few or too many products. Both of these externalities are closely related to the conditions for monopolistic competition. The former arises because a new firm would offer a product different from those of the existing firms. The latter arises because firms post a price above marginal cost and, therefore, are always eager to sell additional units. Conversely, because perfectly competitive firms produce identical goods and charge a price equal to marginal cost, neither of these externalities exists under perfect competition. In the end, we can conclude only that monopolistically competitive markets do not have all the desirable welfare properties of perfectly competitive markets. That is, the invisible hand does not ensure that total surplus is maximized under monopolistic competition. Yet because the inefficiencies are subtle, hard to measure, and hard to fix, there is no easy way for public policy to improve the market outcome.

单选题(If) it receives (enough) rain at the proper time, hay (will grow) quickly (as) grass.

单选题In the face of the conclusive evidence he admitted ______ an old man of sixty, who was crossing the street. A. to run over and injure B. to have run over and injured C. about running over and injuring D. having run over and injuring

单选题Pepys and his wife Jane had asked some friends to dinner on Sunday, September 2nd, 1666. They were up very late on the Saturday evening, getting everything ready for the next day, and while they were busy they saw the glow of a fire start in the sky. By 3 o'clock on the Sunday morning, its glow had become so bright that Jane woke her husband to watch it. Pepys slipped on his dressing gown and went to the window to watch it. It seemed fairly far away, so after a time he went back to bed. When he got up in the morning, it looked, as though the fire was dying down, though he could still see some flames. So he set to work to tidy his room and put his things back where he wanted them. While he was doing this, Jane came in to say that she had heard the fire was a bad one; three hundred houses had been burned down in the night and the fire was still burning. Pepys went out to see for himself. He went to the Tower of London and climbed up on a high part of the buildings so that he could see what was happening. From there, Pepys could see that it was, indeed, a bad fire and that even the houses on London Bridge were burning. The man of the Tower told him that the fire had started in a baker's shop in Pudding Lane; the baker's house had caught fire from the overheated oven and then the flames had quickly spread to the other houses in the narrow lane. So began the Great Fire of London, a fire that lasted nearly five days, destroyed most of the old city and ended, so it is said, at Pie Corner.

单选题Text 4 All couples have problems and disagreements, so it's critical that they learn how to communicate about them in a way that will be helpful instead of making them worse. I do not believe that prescribing specific techniques for communicating is as helpful as focusing on the core attitudes behind the communication. My thoughts on effectively communicating about ANY difficult issue are in keeping with the ideas I used in the "assertiveness training" I did back in the 70s. What I learned was that I could tell people the "correct" words to use and "correct" body language, etc. to be "assertive" —but none of it worked unless it came from "inside" the person. In other words, your ability to communicate has more to do with your attitudes and beliefs about your "right to know" and the degree of "equality" in the relationship (or lack thereof) and the degree of "caring" involved between the two people than in whatever actual words or techniques you use. All these things are FAR more important than the "skills". You can't just "put on the skills like a coat" and have them work. As I said, the words need to come as an outgrowth of an attitude of genuinely wanting to effectively work on whatever problem is being discussed. Another similarity between learning how to effectively discuss a problem and how people learn to talk in an assertive manner is that even if you say everything "just right" (in accordance with the guidelines for using good communication skills), there is no guarantee that the other person will receive it in the way it is intended. For instance, with assertiveness, someone could perfectly execute an "assertive" conversation and still have it be interpreted as being "aggressive". One way of determining the specific words that are more likely to be effective is to think in terms of the "ego states" as defined by transactional analysis: "parent, adult, and child". You'll have more likelihood of success by approaching the discussion from all "adult", problem-solving way of talking, while avoiding using the "judgmental" words of a "parent" or the "hurt feelings" words of a "child". The bottom line is that you don't need specific communication skills so much as you need to approach any conversation with a certain attitude: that the clear goal is to "improve the relationship" rather than to just "criticize" and/or "change" the other person. With that spirit, you have a better chance of success; without it, all the communication skills in the world won't be enough.

单选题The policemen went into action ______ they heard the alarm. A. promptly B. presently C. quickly D. directly

单选题It is more important that she should be free ______ she should live a luxurious life.

单选题Barbara: Your help means everything. Just don't know I'll ever repay you. Kenneth: ______ . It's nothing! A. It's no big deal B. It's not a big thing to do C. It's worth mentioning D. It's not worth talking about

单选题(Economist) Adam Smith (published) his book The Wealth of Nations in 1776, (a year) also (notably) for the Declaration of Independence.

单选题Brazil has become one of the developing world"s great successes at reducing population growth—but more by accident than design. While countries such as India have made joint efforts to reduce birth rates, Brazil has had better result without really trying, says George Martine at Harvard. Brazil"s population growth rate has dropped from 2. 99% a year between 1951 and 1960 to 1. 93% a year between 1981 and 1990, and Brazilian women now have only 2. 7 children on average. Martine says this figure may have fallen still further since 1990, an achievement that makes it the envy of many other Third World countries. Martine puts it down to, among other things, soap operas (通俗电视连续剧) and installment (分期付款) plans introduced in the 1970s. Both played an important, although indirect, role in lowering the birth rate. Brazil is one of the world"s biggest producers of soap operas. Globo, Brazil"s most popular television network, shows three hours of soaps six nights a week, while three others show at least one hour a night. Most soaps are based on wealthy characters living the hig;h life in big cities. "Although they have never really tried to work in a message towards the problems of reproduction, they describe middle and upper class values—not many children, different attitudes towards sex, women working," says Martine. "They sent this image to all parts of Brazil and made people conscious of other patterns of behavior and other values, which were put into a very attractive package. " Meanwhile, the installment plans tried to encourage the poor to become consumers. "This led to an enormous change in consumption patterns and consumption was incompatible (不相容的) with unlimited reproduction," says Martine. (293 words)

单选题The local people could hardly think of any good way to ______. poverty they had endured. A. shake off B. ward off C. put off D. take off

单选题Change, or the ability to (31) oneself to a changing environment is essential (32) evolution. The farmer whose land is required for housing or industry must adapt himself: he can transfer to another place and master the problems (33) to it; he can change his occupation, perhaps (34) a period of training; or he can starve to death. A nation which can't adapt its trade or defense requirements to (35) world conditions faces an economic and military disaster. Nothing is fixed and permanently stable. (36) must be movement forward, which is progress of a sort, and movement backward, which is decay and deterioration. In a changing world, tradition can be a force for good or for evil. (37) long as it offers a guide, it helps the ignorant and the uninformed to take a step (38) and, thereby adapt themselves to (39) circumstances. But if we make an idol of tradition, it ceases to be a guide. It becomes an obstacle (40) on the path of course. Man is to accept the help which tradition can give but to be well aware of its limitations in a changing world.

单选题Despite his occasional fondness for gambling, he is still considered as a good boy ______.

单选题The professor's lecture was so ______ that some of the students fell asleep during the class.

单选题Speaker A：Peter, I'm awfully sorry. I won't be able to come this Friday. Speaker B: What's the matter? ______ A. Nothing wrong, I hope. B. I'm really sorry for that. C. It's all right with me. D. You can come some other time.

单选题On the local market,______fruits and vegetables are now commonly sold.