单选题Sometimes it is advisable to book hotels in advance.

单选题The curious looks from the strangers around her made her feel uneasy .

单选题{{B}}第三篇{{/B}} {{B}}Snow Ranger{{/B}} The two things — snow and mountains — which are' needed for a ski area are the two things that cause avalanches, large mass of snow and ice crashing' down the side of a mountain — often called "White Death." It was file threat of the avalanche and its record as a killer of man in the western mountains that created the snow ranger. He first started on avalanche control work in the winter of 1937 — 1938 at Alta, Utah, in Wasatch National Forest. This mountain valley was becoming well known to skiers. It was dangerous. In fact, more than 120 persons had lost their lives in 1936 and another 200 died in 1937 as a result of avalanches before it became a major ski area. Thus, development of Alta and other major ski resorts in the west was dependent uponcontrolling the avalanche. The Forest Service set out to do it, and did, with its corps of snow rangers. It takes many things to make a snow ranger. The snow ranger must be in excellent physical condition. He must be a good skier and a skilled mountain climber. He should have at least a high school education, and the more college courses in geology, physics, and related fields he has, the better. He studies snow, terrain, wind, and weather. He learns the conditions that produce avalanches. He learns to forecast avalanches and to bring them roaring on down the mountainsides to reduce their killing strength. The snow ranger learns to do this by using artillery, by blasting with TNT, and by the difficult and skillful art of skiing avalanches down. The snow ranger, dressed in a green parka which has a bright yellow shoulder patch, means safety for people on ski slopes. He pulls the trigger on a 75 mm. Recoilless rifle, skis waist deep in powder testing snow stability, or talks with the ski area's operator as he goes about his work to protect the public from the hazards of deep snow on steep mountain slopes.

单选题Major earthquakes are among nature's most devastating (破坏性的) events, causing an incalculable loss of life and property.A. unmentionableB. unprofitableC. impossibleD. immeasurable

单选题A central objective of the developed country was to alleviate the problems of the urban poor.A. lessenB. identifyC. overcomeD. regulate

单选题Please Fasten Your Seatbelts Severe turbulence (湍流) can kill aircraft passengers. Now, in test flights over the Rocky Mountains, NASA．(美国航空航天局) engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it. Clear-air turbulence often catches pilots by surprise. Invisible to radar, it is difficult to forecast and can hurl (用力抛出去) passengers about the cabin. In December 1997, one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 metres in a few seconds. However, passengers can avoid serious injury by fastening their seatbelts. "It is the only antidote (对策) for this sort of thing," says Rod Bogue, project manager at NASA's Dryden Flight Research Center in Edwards, California. The centre's new turbulence detector is based on lidar, or laser radar. Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air. The technique depends on the Doppler effect. The wavelength of the light shifts according to the speed at which the particles are approaching. In calm air, the speed equals the plane's airspeed. But as the particles swirl (打漩) in rough air, their speed of approach increases or decreases rapidly. The rate of change in speed corresponds to the severity (激烈程度) of the turbulence. In a series of tests that began last month, a research jet flew repeatedly into disturbed air over the mountain ridges (山脉) near Pueblo, Colorado. The lidar detector spotted turbulence between 3 and 8 kilometres ahead, and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered. Bogue says that he had "a comfortable amount of time" to fasten his seatbelt. The researchers are planning to improve the lidar's range with a more powerful beam. The system could be installed on commercial aircraft in the next few years.

单选题There is enough space for me to put my new furniture in the roomA. placeB. windowC. roomD. area

单选题It is laid down in the regulations that all members must carry their membership cards at all times. A．suggested B．warned C．stated D．described

单选题The water in this part of the river has been contaminated by sewage (污水).

单选题All the flats in the building had the same {{U}}layout{{/U}}. A. color B. arrangement C. size D. function

单选题{{B}}第二篇{{/B}} {{B}}Stress Level Tied to Education Level{{/B}} People with less education suffer fewer stressful days, according to a report in the current issue of the Journal of Health and Social Behavior. However, the study also found that when less-educated people did suffer stress it was more severe and had a larger impact on their health. From this, researchers have concluded that the day-to-day factors that cause stress are not random. Where you are in society determines the kinds of problems that you have each day, and howwell you will cope with them. The research team interviewed a national sample of 1,031 adults daily for eight days about their stress level and health. People without a high school diploma reported stress on 30 percent of the study days, people with a high school degree reported stress 38 percent of the time, and people with college degrees reported stress 44 percent of the time. "Less advantaged people are less healthy on a daily basis and are more likely to have downward tums in their health." lead researcher Dr. Joseph Grzywacz,of Wake Forest University Baptist Medical Center, said in a prepared statement. "The downward tums in health were connected with daily stressors. and the effect of daily stressors on their health is much more devastating for the less advantaged." Grzywacz suggested follow-up research to determine why less-educated people report fewer days of stress when it is known their stress is more acute and chronic. "If something happens every day, maybe it's not seen as a stressor" Grzywacz says. "Maybe it is just life." stressor n.紧张刺激物 devastating adj.毁灭性的 follow-up n. (对病人的)随访

单选题I' m speaking Uon behalf of/U my friend John.

单选题Thursday, the terrible noise was Usubstituted/U by the grim, steady hum of search and recovery.

单选题Credit Card Only Works When Spoken to A credit card that will not work unless it hears its owner"s voice could become an important weapon in the fight against fraud. The card requires users to give a spoken password that it recognizes using a built-in voice—recognition chip. The idea is to prevent thieves using a stolen card or fraudsters using someone else"s credit card details to buy goods online. A model built by engineers at Beepcard in Santa Monica, California, represents the first attempt to pack a microphone, a loud speaker, a battery and a voice-recognition chip into a standard-sized credit card. They are not quite there yet: the card is the length and width of an ordinary credit card, but it is still about three times as thick. Alan Sege, Beepcard"s CEO, says the company now plans to use smaller chips to slim it down to normal thickness. The voice card is based on an earlier Beepcard technology designed to prevent fraud in online transactions. This earlier card has no microphone, but has a built-in loudspeaker that it uses to "squawk" (发出叫声) a voice ID signal via a computer"s microphone to an online server. By verifying (证实) that the signal matches the card details, the server can establish that the user is not simply keying in ... a credit card number but actually has the card to hand. The ID code changes each time the card is used in a pre-ordered sequence that only the server knows. This prevents fraudsters recording the beeps, noting the card details and then playing back the audible ID when the key in the details later. But this earlier technology cannot prevent fraudulent use of stolen cards. The new one can. The new voice card also identifies itself by-its ID squawk, but it will not do this until it has verified the legitimate user"s spoken password. Thieves will be unable to use the card because even if they knew the password they would have to be unable to copy the owner"s voice with a high degree of accuracy. The challenge for Beepcard has been to develop voice—recognition and audio circuitry that can be powered by a mini battery embedded in a credit card. To maximize battery life, the electronics are only switched on when the card is being used. Pressing a button on the card"s surface prompts it to utter "Say your password" in female voice. If the voice-recognition software proves that the password is authentic, it sends its ID squawk which the server then identifies, allowing the transaction to proceed.

单选题What were the effects of the decision she had made?

单选题She found me very {{U}}dull{{/U}}. A. dirty B. sleepy C. lazy D. boring

单选题 阅读下面这篇短文，短文后列出了7个句子，请根据短文的内容对每个句子作山判断。如果该句提供的是正确信息，请选择A项；如果该句提供的是错误信息，请选择B项；如果该句的信息文章中没有提及，请选择C项。 {{B}}Bees and Color{{/B}} On our table in the garden we put a blue card, and all around this blue card we put a number of different gray cards. These gray cards are of all possible shades of gray land include white and black. on each card a watch-glass is placed .The watch-glass on the blue card has some syrup (果汁) in it; all the others are empty. After a short time bees find the syrup, and they come for it again and again. Then, after some hours, we take away the watch-glass of syrup which was on the bluecard and put an empty one in its place. Now what do the bees do? They still go straight to the blue card, although there is no syrup there. They do not go to any of the gray cards, in spite of the fact that one of the gray cards is of exactly the same brightness as the blue card. Thus the bees do not mistake any shade of gray. for blue. In his way we have proved that they do really see blue as a color. We can find out in just the same way what other colors bees can see. It turns out that bees can see various colors, but these insects differ from us as regards their color-sense in two very interesting ways. Suppose we train bees to come to a red card, and, having done so, we put the red card on the table in the garden among the set of different gray cards. This time we find that the bees mistake red for dark gray or black. They cannot distinguish between them. This means that red is not a color at all for bees; for them it is just dark gray or black. That is one strange fact; here is another. A rainbow is red on one edge, violet on the other. Outside the violet of the rainbow there is another color which we cannot see at all. This color beyond the violet, invisible to us, is called the ultra-violet. Although it is invisible, we know that the ultra -violet is there because it affects a photographic plate. Now, although we are unable to see ultra -violet light, bees can do so; for them ultra -violet is a colon Thus bees see a color which we cannot even imagine. This has been found out by training bees to come for syrup to various parts of a spectrum, or artificial rainbow, thrown by a prism on a table in a dark room. In such an experiment the insects can be taught to fly to the ultra-violet, which for us is just darkness.

单选题More than one-third of the Chinese in the United States live in California, predominantly in San Francisco.

单选题Eleanor Roosevelt urged legislation to assist the poor and oppressed.

单选题This gold mine was discovered by accident.A. by airB. by chanceC. at largeD. at ease