单选题 The term "g" (general intelligence) represents a measure of overall cognitive ability across a variety of tests. It's not the same as IQ but it does tend to correlate. Everyone agrees that "g" tends to run in families. But is this down to genetics or to environmental influences? However, no single gene has yet been conclusively linked to intelligence. Rather it appears to be a case of complex interactions on many levels between many different genes. Identical twins have exactly the same genes, while non-identical twins share about half their genes. Another feature of twins that makes them an ideal choice for studies is that they tend to be raised in pretty much the same environment. If a particular feature is the same in identical twins, but not m non-identical twins, then chances are it's mainly genes that are controlling that feature. So what do the twin studies show? Well, first degree relatives tend to have "g" correlation of about 0.4-0.5. (Perfect correlation is 1; correlation of 0 means that the two things in question are totally unrelated). Identical twins have a correlation of 0.85, while for non-identical twins it's about 0.6. Which suggests that genes play a very important role, but are not the only factor, since if they were, the correlation between identical twins would be 1. Identical twins reared apart are almost as similar in "g" scores as those reared together. Adopted children and their adoptive parents have a "g" correlation of zero, while adopted children and their biological parents tend to have the same correlations as any parent-child pair. So although genes don't seem to be the only thing affecting intelligence, their effects seem to be constant and apparently not overridden by environment. Does heritability of intelligence alter over a lifetime? Remarkably, it appears so. "g" heritability climbs gradually from 20% in babies to 40% in children, peaking at 60% in adults. Why this should be is still a matter of speculation. It's been suggested that as our cognitive abilities become more complex, new genes may come into play that were not needed when brain functions were less sophisticated. Or individuals may be drawn towards environments that fit with their genetic makeup, as time goes by and genetic effects that started out small in childhood build up together during adulthood.

单选题To me, St. Francis embodied the ideal {{U}}blend{{/U}} of spirituality and public service. A. composition B. mixture C. elaboration D. speculation

单选题All experts agree that the most important consideration with diet drugs is carefully ______ the risks and benefits. A. weighing B. valuing C. evaluating D. distinguishing

单选题A.Hewillnottaketheshowerbeforethemeeting.B.Hewillnotgotothemeetingatall.C.Hewillhavetoattendthemeeting.D.Hewillbelateforthemeetingagain.

单选题He couldn't ______ his curiosity to see what was in the box. A. retain B. restrain C. restrict D. represent

单选题Without clear guidelines ______, executives of hospitals are sometimes at a loss what to do. A. in order B. in place C. in need D. in trouble

单选题The utilization of hydroelectric resources should be {{U}}stepped up{{/U}}. A. sustained B. increased C. supported D. encouraged

单选题The investor would suffer a lot from a television series that was heavily invested in but never came off. A. was released B. proved satisfactory C. failed completely D. won awards

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单选题 Even during the horse and carriage days, traffic in big cities was often heavy. Police officers had to be stationed full time directing traffic at busy intersections. The world's first traffic light came into being before the automobile was in use, and traffic consisted only of pedestrians, carriages and wagons. On December 10, 1868, the first traffic lights were installed outside the British Houses of Parliament in London, by the railway engineer J. P. Knight. They resembled railway signals of the time, with signaling arms and red and green gas lamps for night use. The gas lantern was turned with a lever at its base so that the appropriate light faced traffic. Unfortunately, it exploded on 2 January 1869, injuring the policeman who was operating it. The modern electric traffic light is an American invention. As early as 1912 in Salt Lake City, Utah, policeman Lester Wire invented the first red-green electric traffic lights. On 5 August 1914, the American Traffic Signal Company installed a traffic signal system. It had two colors, red and green, and a buzzer, based on the design of James Hoge, to provide a warning for color changes. The design by James Hoge allowed police and fire stations to control the signals in case of emergency. The first four-way, three-color traffic light was created by police officer William Potts in Detroit, Michigan in 1920. Timers on traffic lights were first seen in Taipei, China, and then brought to the U.S. after an engineer discovered its use. Though uncommon in most American urban areas, timers are still used in some other Western Hemisphere countries. Timers are useful for drivers to plan if there is enough time to attempt to cross the crossroad before the light turns red and the amount of time before the light turns green. The colors of the traffic lights are psychologically associated with the message they are meant to transmit. Red is classically seen as a color representing danger or caution. (There are countless phrases and idioms that use "red" as a message of the bad or unknown--"in the red" and "seeing red.") Green, on the other hand, is a reassuring color in most cultures--the color of nature and growth; of harmony, freshness, and fertility. Green has a strong emotional correspondence with the idea of safety, and was intuitively chosen to guide pedestrians responsibly through an intersection.

单选题{{B}}Directions:{{/B}} {{I}}In this section you will hear two mini-talks. At the end of each talk, there will be some questions. Both the talks and the questions will be read to you only once. After each question, there will be a pause. During the pause, you must choose the best answer from the four choices given by marking the corresponding letter with a single bar across the square brackets on your Machine-scoring Answer Sheet. {{/I}}

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单选题Teachers of {{U}}primary{{/U}} schools should manage to be patient, friendly, tolerant and experienced. A. principal B. elementary C. leading D. secondary

单选题Passage One The study of genetics has given rise to a profitable new industry called biotechnology. As the name suggests, it blends biology and modem technology through such techniques as genetic engineering. Some of the new biotech as they are called, specialize in agriculture and are working enthusiastically to patent seeds that give a high yield, that resist disease, drought, and frost, and that reduce the need for hazardous chemicals. If such goals could be achieved, it would be most beneficial. But some have raised concerns about genetically engineered crops. "In nature, genetic diversity is created within certain limits," says the book Genetic Engineering, Food, and Our Environment. "A rose can be crossed with a different kind of rose, but a rose will never cross with a potato. Genetic engineering, on the other hand, usually involves taking genes from one species and inserting them into another in an attempt to transfer a desired property or character. This could mean, for example, selecting a gene which leads to the production of a chemical with antifreeze properties from an arctic fish, and joining it into a potato or strawberry to make it frost-resistant. It is now possible for plants to be engineered with genes taken from bacteria, viruses, insects, animals or even humans." In essence, then, biotechnology allows humans to break the genetic walls that separate species. Like the green revolution, what some call the gene revolution contributes to the problem of genetic uniformity—some say even more so because geneticists can employ techniques such as cloning and tissue culture, processes that produce perfectly identical copies, or clones. Concerns about the erosion of biodiversity, therefore, remain. Genetically altered plants, however, raise new issues, such as the effects that they may have on us and the environment. "We are flying blindly into a new era of agricultural biotechnology with high hopes, few constraints, and little idea of the potential outcomes," said science writer Jeremy Rifkin.

单选题 The biosphere is the name biologists give to the sort of skin on the surface of this planet that is inhabitable by living organisms. Most land creatures occupy only the interface between the atmosphere and the land; birds extend their range for a few hundred feet into the atmosphere; burrowing invertebrates such as earthworms may reach a few yards into the soil but rarely penetrate farther unless it has been recently disturbed by men. Fish cover a wider range, from just beneath the surface of the sea to those depths of greater than a mile inhabited by specialized creatures. Fungi(真菌) and bacteria are plentiful in the atmosphere to a height of about half a mile, blown there by winds from the lower air. Balloon exploration of the stratosphere (同温层) as long ago as 1936 indicated that moulds and bacteria could be found at heights of several miles, recently the USA's National Aeronautics and Space Administration has detected them, in decreasing numbers, at heights up to eighteen miles. They are pretty sparse at such levels, about one for every two thousand cubic feet, compared with 50 to 100 per cubic foot at two to six miles (the usual altitude of jet aircraft), and they are almost certainly in an inactive state. Marine bacteria have been detected at the bottom of the deep Pacific trench, sometimes as deep as seven miles; they are certainly not inactive. Living microbes have also been obtained on land from cores of rock drilled (while prospecting for oil) at depths of as much as 1,200 feet. Thus we can say, disregarding the exploits of astronauts, that the biosphere has a maximum thickness of about twenty-five miles. Active living processes occur only within a compass of about seven miles, in the sea, on land and in the lower atmosphere, but the majority of living creatures live within a zone of a hundred feet or so. If this planet were scaled down to the size of an orange, the biosphere, at its extreme width, would occupy the thickness of the orange-colored skin, excluding the pith. In this tiny zone of our planet takes place the multitude of chemical and biological activities that we call life. The way in which living creatures interact with each other, depend on each other or compete with each other, has fascinated thinkers since the beginning of recorded history. Living things exist in a fine balance which is often taken for granted—for, from a practical point of view, things could not be otherwise. Yet it is a source of continual amazement to scientists because of its intricacy and delicacy. The balance of nature is obvious most often when it is disturbed, yet even here it can seem remarkable how quickly it readjusts itself to a new balance after a disturbance. The science of ecology—the study of the interaction of organisms with their environment—has grown up to deal with the minutiae of the balance of nature.

单选题Unpleasant symptoms can cause the smoker to resume smoking to raise the levels of nicotine in the blood.

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单选题Even if you possess these qualities, you will not achieve your goal without {{U}}uncompromising{{/U}} effort. A. unyielding B. uninhabitable C. unproductive D. unsubstantial

单选题A loan refers to anything given on condition of its return or repayment of its ______. A. excess B. debt C. currency D. equivalent

单选题These intelligence officers tried a______of persuasion and force to get the information they wanted. A. combination B. collaboration C. conviction D. confrontation