单选题Today people usually acquire a large amount of botanical knowledge from textbooks.

单选题Are G8 Climate Targets Realistic? The commitment by G8 nations to reduce greenhouse gas emissions by 80% by 2050. Nothing else than a top -to -bottom refit can do the job. Virtually all electricity generation will have to come from renewables, nuclear power or so - called" clean" coal—if that technology can be made to work on a commercial scale. The amount of electricity generated in Western countries will have to rise significantly— doubling or even trebling—as transport and the heating systems for homes and businesses switch away- fromfossilfuels. Alongside a re - fuelling revolution would go a frugality revolution, as societies put an end to energy wastage. But so far, leaders have not talked collectively of how start this revolution. And that is what makes some suspicious that the big targets are more about dressing windows than about re - writing the world's energy rulebook. Another generator of suspicion is that the target is dim in the future—a time when. as the UK's climate and energy secretary Ed Miliband admits, none of the leaders setting the target are likely to be in office and able to be held accountable. Do governments set targets on, say, the number of people in higher education 41 year in advance? Generally speaking, they do not. The EU and Japan have set 2020 targets domestically, and legislation going through the US Congress should lead to a commitment from Washington too. Many EU nations are in reality struggling to meet even their far more modest Kyoto Protocol commitments. Funding headache So now, G8 leaders will try to persuade some major developing countries to have global emissions by 2050. Governments such as China's that are concerned about climate impacts may find the figure desirable. But they are unlikely to be impressed with what they see as fine words from the West unmatched by real short- term commitments. Unmatched, too, by money. So if the West wants the developing world to go through its own energy revolution, it is going to have to fund a lot of it. This time developing country governments are likely to want to see the money itself rather than some amorphous pledge.

单选题Some Things We Know about Language Many things about language are a mystery, and many will always remain so. But some things we do know. First, we know that all human beings have a language of some sort. There is no race of men anywhere on earth so backward that it has no language, no set of speech sounds by which the people communicate with one another. Furthermore, in historical times, there has never been a race of men without a language. Second, there is no such thing as a primitive language. There are many people whose cultures are undeveloped, who are, as we say, uncivilized, but the languages they speak are not primitive. In all known languages we can see complexities that must have been tens of thousands of years in developing. This has not always been well understood; indeed, the direct contrary has often been stated. Popular ideas of the language of the American Indians will illustrate. Many people have supposed that the Indians communicated in a very primitive system of noises. Study has proved this to be nonsense. There are, or were, hundreds of American Indian languages, and all of them turn out to be very complicated and very old. They are certainly different from the languages that most of us are familiar with, but they are no more primitive than English and Greek. A third thing we know about language is that all languages are perfectly adequate. That is, each one is a perfect means of expressing the culture of the people who speak the language. Finally, we know that language changes. It is natural and normal for language to change; the only languages which do not change are the dead ones. This is easy to understand if we look backward in time. Change goes on in all aspects of language. Grammatical features change as do speech sounds, and changes in vocabulary are sometimes very extensive and may occur very rapidly. Vocabulary is the least stable part of any language.

单选题It is no use debating the relative merits of this policy.

单选题 Water From the beginning, water has furnished man with a source of food and a highway to travel upon. The first civilizations arose {{U}} {{U}} 1 {{/U}} {{/U}}water was a dominant element in the environment, a challenge {{U}} {{U}} 2 {{/U}} {{/U}}man's ingenuity. The Egyptians invented the 365-day calendar in response to the Nile's annual flooding. The Babylonians, {{U}} {{U}} 3 {{/U}} {{/U}}were among the most famous law-makers in ancient times, invented laws {{U}} {{U}} 4 {{/U}} {{/U}}water usage. Water inspired the Chinese to build a 1,000-{{U}} {{U}} 5 {{/U}} {{/U}}canal, a complex system which, after nearly 2,500 years, remains still practically {{U}} {{U}} 6 {{/U}} {{/U}}and still commands the astonishment of engineers. But {{U}} {{U}} 7 {{/U}} {{/U}}never found complete solutions to their water problems. The Yellow River is also known as "China's Sorrow"; it is so unpredictable and dangerous {{U}} {{U}} 8 {{/U}} {{/U}}in a single flood it has caused a million {{U}} {{U}} 9 {{/U}} {{/U}}. Floods slowed the great {{U}} {{U}} 10 {{/U}} {{/U}}of the Indus River Valley, and inadequate drainage ruined {{U}} {{U}} 11 {{/U}} {{/U}}of its land. Today water dominates man {{U}} {{U}} 12 {{/U}} {{/U}}it always has done. Its presence continues to {{U}} {{U}} 13 {{/U}} {{/U}}the location of his homes and cities; its violent variability can {{U}} {{U}} 14 {{/U}} {{/U}}man or his herds or his crops; its routes links him {{U}} {{U}} 15 {{/U}} {{/U}}his fellows; its immense value may add to already dangerous political conflicts. There are many examples of this in our own time.

单选题Marry is looking for the book she lost yesterday.

单选题After supper we usually take a stroll around the park for about an hour.A. walkB. restC. bathD. breath

单选题I propose that we discussed this at the next meeting.A. requestB. suggestC. demandD. order

单选题If no one objects , Mr.Ben will be the next chairman. ______

单选题The weather last summer was awful.

单选题We were all there when the accident occurred .

单选题Experiments have confirmed the assumption of many executives.

单选题Bob believes that the invasion of the marketplace into the university is undermining fundamental academic values, and that we must act now to halt this decline.

单选题Scientists {{U}}routinely{{/U}} deal with concepts such as uncertainty, probability, and hypothesis.

单选题An old friend called on me the day before yesterday. A. telephoned B. rang C. visited D. saw

单选题They voted to {{U}}abolish{{/U}} the office of second vice-president.

单选题Computer Mouse The basic computer mouse is an amazingly clever invention with a relatively simple design that allows us to point at things on the computer and it is very productive. Think of all the things you can do with a mouse like selecting text for copying and pasting, drawing, and even scrolling on the page with the newer mice with the wheel. Most of us use the computer mouse daily without stopping to think how it works until it gets dirty and we have to learn how to clean it. We learn to point at things before we learn to speak, so the mouse is a very natural pointing device. Other computer pointing devices include light pens, graphics tablets and touch screens, but the mouse is still our workhorse. The computer mouse was invented in 1964 by Douglas Englehart of Stanford University. As computer screens became more popular and arrow keys were used to move around a body of text, it became clear that a pointing device that allowed easier motion through the text and even selection of text would be very useful. The introduction of the mouse, with the Apple Lisa computer in 1983, really started the computer public on the road to relying on the mouse for routine computer tasks. How does the mouse work? We have to start at the bottom, so think upside down for now. It all starts with the mouse ball. As the mouse ball in the bottom of the mouse rolls over the mouse pad, it presses against and turns two shafts. The shafts are connected to wheels with several small holes in them. The wheels have a pair of small electronic light-emitting devices called light- emitting diodes (LED) mounted on either side. One LED sends a light beam to the LED on the other side. As the wheels spin and a hole rotates by, the light beam gets through to the LED on the other side. But a moment later the light beam is blocked until the next hole is in place. The LED detects a changing pattern of light, converts the pattern into an electronic signal, and sends the signal to the computer through wires in a cable that goes out of the mouse body. This cable is the tail that helps give the mouse its name. The computer interprets the signal to tell it where to position the cursor on the computer screen. So far we have only discussed the basic computer mouse that most of you probably have or have used. One problem with this design is that the mouse gets dirty as the ball rolls over the surface and picks up dirt. Eventually you have to clean your mouse. The newer optical mice avoid this problem by having no moving parts.

单选题Atlas was the giant who held up the sky.

单选题The Influence of Western Movie Why does the Western movie especially have such a hold (影响) on our inclination? Chiefly, because it offers serious insights into the problem of violence such as can be found almost nowhere else in our culture. One of the well-known peculiarities of modem civilized opinion is its refusal to acknowledge the value of violence. This refusal is a virtue, but like many virtues it involves a certain deliberate blindness and it encourages hypocrisy (虚伪). We train ourselves to be shocked or bored by cultural images of violence, and our very concept of heroism tends to be a passive one. We are less drawn to the brave young men who kill large numbers of our enemies than to the heroic prisoners who endure torture without surrendering. And in the criticism of popular culture, the presence of images of violence is often assumed to be in itself a sufficient ground for condemnation. These attitudes, however, have not reduced the element of violence in our culture but have helped to free it from morn control by letting it take on the air of "liberation". The celebration of acts of violence is left more and more to the irresponsible. The gangster (匪徒) movie, with its numerous variations belongs to a cultural "underground" which praises violence aid sets it against all our higher social attitudes. It is a more "modern" style than the Western movie, perhaps even more profound, because it confronts industrial society on its own ground-the city and because, like much of our advanced art, it gains its effects by a coarse insistence on its own narrow logic. But it is anti-social resting on fantasies of irresponsible freedom. If we are brought finally to concede to the denial of these fantasies, it is only because they have been shown to be dangerous, not because they have given way to higher values of behavior. In war movies, certainly, it is possible to present violence within a framework of responsibility. But there is the disadvantage that modern war is a co-operative enterprise in which violence is largely impersonal and heroism belongs to the group more than to the individual. The hero of a war movie is most often simply a leader supposed to be brave; you are supposed to get the job done and stay alive (this too, of course, is a kind of heroic posture, but a new and "practical" one). At its best, the war movie may represent a more civilized point of view than the Western, and if it were not continually spoiled by ideological sentimentality we might hope to find it developing into a higher form of drama. But it cannot supply the values we seek in the Western.

单选题A Powerful Influence There can be no doubt at all that the Internet has made a huge difference to our lives. Parents are worried that children spend too much time playing on the Internet, hardly 1 doing anything else in their spare time. Naturally, parents are 2 to find out why the Internet is so attractive, and they want to know if it can be 3 for their children. Should parents worry if their children are spending that much time 4 their computers? Obviously, if children are bent over their computers for hours, absorbed 5 some game, instead of doing their homework, then something is wrong. Parents and children could decide how much use the child should 6 use of the Internet, and the child should give his or her 7 that it won"t interfere with homework. If the child is not 8 to this arrangement, the parent can take more drastic 9 dealing with a child"s use of the Internet is not much different from 10 any other soft of bargain about behaviour. Any parent who is 11 alarmed about a child"s behaviour should make an appointment to 12 the matter with a teacher. Spending time in front of the screen does not necessarily 13 a child"s performance at school. Even if a child is 14 crazy about using the Internet, he or she is probably just 15 through a phase, and in a few months there will be something else to worry about!