托福习题练习
| 托福考试易错题（2019/10/11） |
| 第1题：Questions 41-50 InDeath Valley,California, one of the hottest, most arid places in NorthAmerica, there is much salt, and salt can damage rocks impressively. Inhabitants of areas elsewhere, where streets and highways are salted to control ice, are familiar with the resulting rust and deterioration on cars. That attests to the chemically corrosive nature of salt, but it is not the way salt destroys rocks. Salt breaks rocks apart principally by a process called crystal prying and wedging. This happens not by soaking the rocks in salt water, but by moistening their bottoms with salt water. Such conditions exist in many areas along the eastern edge of centralDeath Valley. There, salty water rises from the groundwater table by capillary action through tiny spaces in sediment until it reaches the surface. Most stones have capillary passages that suck salt water from the wet grounD、Death Valley provides an ultra-dry atmosphere and high daily temperatures, which promote evaporation and the formation of salt crystals along the cracks or other openings within stones. These crystals grow as long as salt water is available. Like tree roots breaking up a sidewalk, the growing crystals exert pressure on the rock and eventually pry the rock apart along planes of weakness, such as banding in metamorphic rocks, bedding in sedimentary rocks, or preexisting or incipient fractions, and along boundaries between individual mineral crystals or grains.Besides crystal growth, the expansion of halite crystals(the same as everyday table salt) by heating and of sulfates and similar salts by hydration can contribute additional stresses.A、rock durable enough to have withstood natural conditions for a very long time in other areas could probably be shattered into small pieces by salt weathering within a few generations. The dominant salt inDeath Valley is halite, or sodium chloride, but other salts, mostly carbonates and sulfates, also cause prying and wedging, as does ordinary ice. Weathering by a variety of salts, though often subtle, is a worldwide phenomenon. Not restricted to arid regions, intense salt weathering occurs mostly in salt-rich places like the seashore, near the large saline lakes in theDry Valleys ofAntarctica, and in desert sections ofAustralia, New Zealand, and centralAsiA、 The word "it" in line 9 refers toA．salty water B．groundwater table C．capillary action D．sediment |
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| 第2题：Which office helps overseas students with their particular problems A、SportsClu B、 B、Union Societies. C、Accommodation Office. D、Welfare Office. |
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| 第3题：TOEFL Reading Passage 1 The Snake’s Forked Tongue 1. One of the most intriguing physical characteristics of snakes is their forked tongues. While this trait is also shared by some types of lizards, all snake species exhibit split tongues, which usually have a more pronounced fork than those of lizards.Any observer of snakes has no doubt noticed that they often stick their tongues out of their mouths, flick them up and down in the air, and then retract them. In fact, due to a slight indentation in the upper jaw, many species can protrude their tongues without even opening their mouths. 2. The explanation for this behavior remained unknown for centuries, giving rise to many folk superstitions. For example, the forked tongue has become synonymous with deceit, from the idea that two separate tongues would enable a creature to voice two contrasting ideas at the same time.Another popular misconception is that snakes sting other animals with their tongues. Recently, though, scientists uncovered the truth about the forked tongue, and its actual use is much less sinister. 3. Snakes differ greatly from humans on a sensory level. On the one hand, their eyesight is poor and they lack outer ears so they cannot hear with much volume or clarity, but, on the other, some have the ability to "see" and hunt in the dark by sensing the body heat of their prey. In addition, snakes have a method of smelling that is peculiar in that it is actually performed by the tongue rather than by the nostrils and nasal cavities, which in fact undertake other functions, such as breathing. When a snake flicks its tongue around in the air, it is actually snaring chemical particles, which can be thought of as odors. Next, the snake brings its tongue back in and places it against the roof of its mouth, where there are two small openings that correspond to the two tips of the forked tongue. These make up the snake’s Jacobson’s organ, a kind of chemoreceptor that analyzes the chemical odors on the tongue and sends this information to the snake’s brain. 4. This technique for "smelling" the surrounding environment is truly unique, but even more amazing is the reason why the snake’s tongue is forkeD、By spreading the tips apart when the tongue is flicked out, each samples chemical particles from a slightly different position in the air and brings them back to the Jacobson’s organ.The organ then determines which tip was exposed to a larger amount of the particles in question, and this data tells the snake where the source of the odor can be founD、In other words, if the tongue’s right tip contains more of the particles, such as those of an animal’s chemical odor, the snake knows that to find the animal it must travel to the right, not to the left. 5. Obviously, the ability of snakes to pursue scents in this fashion is very useful in hunting,  Similarly, if the odor the snake perceives belongs to a predator, it is able to adjust its course to steer clear of the danger,  Another suggested use of snakes’ sense of smell is that it aids them in ascertaining the locations of communal dens*, where snakes reside in groups during the winter months. 6. However, scientists who have studied the chemoreception process in snakes believe its most vital role is in the detection of mates.Because most snakes lead solitary lives for much of the year, the capability of males to track down females duri |
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| 第4题：Bacterial (cultures) are used (commercially) in the (preparation) of food products (such)that yogurt ,sour cream ,and vinegar. A、cultures B．commercially C．preparation D．such |
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| 第5题：{{B}}Set 2{{/B}} Consumer electronics: New sports equipment, from tennis rackets to running shoes, uses processing power to enhance performance. Is that fair Why should aspiring athletes stand on the sidelines when a spot of electronic assistance can put them in the middle of the game That is the question many sports-equipment makers are asking as they sense an opportunity to boost their sales with high-tech products. You could call it the revenge of the nerds: a new wave of microchip-equipped sporting goods promises to enhance the performance of novices and non-sporting types alike--and could even make difficult sports easier. Take cross-country skiing. Victor Petrenko, an engineer atDartmouthCollege’s Ice Research Lab in New Hampshire, has invented some smart ski-brakes that, he believes, will increase the popularity of cross-country skiing by making the sport less challenging for beginners. The brakes, currently being tested by a ski manufacturer in theAlps, offer the necessary friction for a bigger "kick-off force" and make the skis less likely to slide backwards in their trucks. To make this happen, an electric current from the bottom of the skis pulses through the ice, melting a thin layer of snow that instantly refreezes and acts as a sort of glue. This is not the only form of smart ski to hit the slopes.Atomic, a leading ski-maker based inAustria, plans to introduce a system later this year that runs a diagnostic safety check to ensure that the ski binding is properly closed, with the result being shown on a tiny built-in liquid-crystal display. Meanwhile, tennis equipment manufacturers are hoping that innovation will bring new zip to their business as well. They certainly need to do something: according to Sport ScanInfo, a market-research firm based in Florida, sales of tennis rackets inAmerica fell 12.5% during the first half of 2004 compared with the first half of 2003. With the ball clearly in their court, researchers at Head, a maker of sporting equipment, have devised a product that should appeal to players suffering from tennis elbow.A、chip inside the racket controls piezo-electric fibres, which convert mechanical energy from the ball’s impact into electrical potential energy. This energy is then used to generate a counter-force in the piezo-electric fibres that causes a dampening effect.All of this, the firm says, translates into less stress on the elbow. Head claims that residual vibrations in the racket are dampened twice as fast as in conventional rackets, reducing the shock experienced by the player’s arm by more than 50%. No doubt purists will object that this is simply not cricket. Rule-makers in many sports are now being forced to consider the implications of equipment that promises to augment athletes’ performance with electronic muscle. The International Tennis Federation, that body is responsible for setting the rules of the game, has specified in its most recent guidelines that "no energy source that in any way changes or affects the playing characteristics of a racket may be built into or attached to a racket". Yet despite such wording, the guideline does not actually eliminate the use of Head’s smart rackets, because there is no external energy source---the damping effect relies solely on energy from the ball’s impact. Though high-tech equipment may cause controversy on the court, tennis clubs have to adhere to the guidelines set for the sport, explains Stuart Miller, the ITF’s technical manager.And if the rules allow self-generated forces to modify a racket’s response, so be it.  Different sports have encou【单选题】： | |