单选题 Transportation use a to Be Much Slower than It Is Now For many years in tile desert, camels used to be the only form of transportation. Before the (51) of modern trains, camel trains used to carry al! the goods for trading between Central Africa and Europe. Traders sometimes (52) to put together camel trains with 10,000 to 15,000 animals. Each animal often carried (53) 400 pounds and it could travel twenty miles a day. This form of transportation was so important (54) camels were called the "ship of the desert". Now modern trains travel across the desert in a very (55) time. One engine can pull as much weight as 135,000 (56) ,in addition, trains use special cars for their load. Refrigerator cars carry food; boxcars carry heavy goods; stock cars carry animals; and tank cars carry oil. (57) travel has changed, too. The earliest planes were biplanes, with two sets of wings. The top speed of this plane was 60 miles per hour. The pilots used to sit or lie on the wings in the open air. The plane (58) sometimes stopped in the middle of a trip. It used to be (59) to fly in bad weather. In snow or in rain, the wings frequently became icy. (60) the plane might go down. Mechanical improvements during the First World War changed airplanes. Monoplanes took the place of biplanes. Pilots flew inside of covered cabins. Still, even these planes were small and expensive. Only (61) people were able to travel in airplanes. Now modern jets make air travel possible for all people. (62) place in the world is more than 1 hours away by jet. Further improvements have (63) the cost of flying, and they have made air travel much safer than it used to be. A modern 707 can carry 170 people and can fly at 600 miles per hour. People (64) used to eat, sleep, or watch movies on airplanes. (65) these things are a normal part of air travel!

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 it and can hurl (用力抛出去) passengers out of 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 meters 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, laser, or 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 (打旋) 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 kilometers 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The most pressing problem that any country faces is how to use its scarce natural resources.A. puzzlingB. difficultC. terrifyingD. urgent

单选题The construction of the bridge goes on very well.A. instructionB. destructionC. conductionD. building

单选题Prohibition in the United States {{U}}ushered in{{/U}} an era of crime and corruption.

单选题Nobody could figure out this problem.A. make outB. think ofC. solveD. discover

单选题______ a book in his hand, he went in from the back door.A. to catchB. catchingC. caughtD. to be caught

单选题Their parents once lived under very severe conditions.

单选题The local government planned to launch a new program to help the poor.

单选题For young children, getting dressed is a {{U}}complicated{{/U}} business. A.personal B.strange C.funny D.complex

单选题The Commission has also begun looking into the {{U}}role{{/U}} of climate.

单选题I thought the rule not allowing women to compete was completely Uabsurd/U.

单选题Reading Something In English When you read to learn English composition, you 【51】 regard the language as the main thing. When you read a 【52】 in English, do you read it for the story or for the English? This is a question that is not so foolish 【53】 it may seem, 【54】 I find that many students of English 【55】 far more attention to the story than to the English. They read and enjoy and 【56】 a long time afterwards remember the story, but do not care to study the use of words and 【57】 in it. For instance, they know the plot (情节) of the story 【58】 , but do not remember a 【59】 sentence in the story and cannot tell what preposition is used before or 【60】 a certain word in the speech of a certain character(人物). Of course, it is all right to read and 【61】 and remember a story, and so long as one 【62】 to know the story only, one need not bother about the language. But the case is quite different 【63】 a student of English. I mean a student of English as distinguished (区别于)from a reader of stories or what is called the general reader. As you may have 【64】 form the above, a student of English should read very 【65】 and regard the language as the main thing.

单选题 Male-Female Expectation about Marriage The differences between men and women clarify why they have different expectations about communication in marriage. For women, talk {{U}} {{U}} 1 {{/U}} {{/U}}intimacy. Marriage is an orgy (狂欢) of {{U}} {{U}} 2 {{/U}} {{/U}}: you can tell your feelings and thoughts, and still be loved. Women's greatest fear is being pushed away. But men live in a hierarchical world, {{U}} {{U}} 3 {{/U}} {{/U}}talk maintains independence and statue. They are on {{U}} {{U}} 4 {{/U}} {{/U}}to protect themselves from being put down and pushed around. This {{U}} {{U}} 5 {{/U}} {{/U}}the paradox of the talkative man who said of his silent wife, "She's the talker." In public settings, he feels challenged to {{U}} {{U}} 6 {{/U}} {{/U}}his intelligence and display his understanding. But at home, where he has {{U}} {{U}} 7 {{/U}} {{/U}}to prove and no one to defend against, he is free to remain {{U}} {{U}} 8 {{/U}} {{/U}}. For his wife, being home means she is free from the worry that something she says might {{U}} {{U}} 9 {{/U}} {{/U}}someone, or spark disagreement, or appear to be showing off; at home she is {{U}} {{U}} 10 {{/U}} {{/U}}to talk. The communication {{U}} {{U}} 11 {{/U}} {{/U}}that endanger marriage can't be fixed by mechanical engineering. They require a new conceptual framework about the {{U}} {{U}} 12 {{/U}} {{/U}}of talk in human relationships. Many of the psychological explanations may not be {{U}} {{U}} 13 {{/U}} {{/U}}, because they tend to blame either women (for not being assertive enough) {{U}} {{U}} 14 {{/U}} {{/U}}, men (for not being in touch with their feelings). A sociolinguistic approach in {{U}} {{U}} 15 {{/U}} {{/U}}male-female conversation is seen as cross-cultural communication allows us to understand the problem and forge solutions without blaming either party.

单选题My sister has a talent for music.A. interestB. limitationC. dreamD. gift

单选题The construction of the railway is said to have been terminated.A. resumedB. endedC. suspendedD. cancelled

单选题Such subjects are not within the scope of this book.

单选题Norman Blamey is an artist of deep convictions .

单选题The Car Cars are an important part of life in the United States. Without a car most people feel that they are poor. And even if a person is poor he doesn"t feel really poor when he has a car. Henry Ford was the man who first started making cars in large numbers. He probably didn"t know how much the car was going to affect American culture. The car made the United States a nation on wheels. And it helped make the United States what it is today. There are three main reasons why the ear becomes so popular in the United States. First of all, the country is a huge one and Americans like to move around in it. The car provides the most comfortable and cheapest form of transportation. With a car people can go anyplace without spending a lot of money. The second reason why cars are popular is the fact that the United States never really developed an efficient and inexpensive form of public transportation. Long-distance trains have never been as common in the country as they are in other parts of the world. Nowadays there is a good system of air-service provided by planes. But it is too expensive to be used frequently. The third reason is the most important one, though. The American spirit of independence is what really made cars popular. Americans don"t like to wait for a bus, or a train or even a plane. They don"t like to have to follow an exact schedule. A car gives them the freedom to schedule their own time. And this is the freedom that Americans want most to have. The gas shortage has caused a big problem for Americans. But the answer will not be a bigger system of public transportation. The real solution will have to be a new kind of car, one that does not use so much gas.

单选题The leaves have been swept into huge heaps.