21 Astronomers have spent hundreds of years searching for signs of life on other planets, using telescopes. When they saw the geography of Mars (火星), they thought they could see canals and that this might be evidence of intelligent life on the planet. More recently, however, spacecraft have been sent there to analyze (分析) the soil for signs of life. The result were negative and astronomers now feel certain that no life exist on the surface of any craft far beyond our solar system （太阳系）I not realistic because of the huge distances.
Unless life comes and visit us, the only way we likely to know of its existence is from radio message. Listening for intelligent extraterrestrial (外星的) or E.T. life is not a new idea, but the techniques now being used offer a much better chance off success than before. Looking for evidence of life in other solar systems now means using special radio receivers called radio telescopes to listen out for message. The idea is that intelligent forms of life would have discovered radio waves and would, like us, be using them to communicate.
Through its research work, NASA(美国国家航空航天局) has develop two means of systematically searching for E.T. life. The first method is to select the closest 800 stars like our sun and to direct a radio telescope to scan each of one them for electromagnetic (电磁) wave. The second way is to survey the entire sky, listening for continuous signals which may come from extraterrestrial life. Scientists are looking in the 100-10,000 MegaHetz(兆赫) frequency range—a range where there are fewer natural radio signals which could interfere (干扰) with transmission (传输). By looking signals in these specific regions, scientists can avoid any confusion that might be caused by receiving a natural radio signal rather than one sent by intelligent life.
NASA’s search in space has already resulted in some discoveries –including new equipment which may help in the development of new communication and medical technologies.
All this, as well as the chance of discovering, has made us feel confident that maybe we are not alone in the universe!
What is the main idea of the passage?
A Astronomers now feel certain that no life exists on the surface of any other planet in our solar system.
B It is realistic to send a spacecraft far beyond our solar system to search for E.T. life.
C There is no E.T. life on Mars.
D Using radio telescopes to listen out for message from E.T. life, scientists have discovered that the new equipment nay help in the development of new communication and medical technologies.
22 It is burning hot in Mali, an island country in Africa, where the highest temperature even reach 55℃, while the average temperature of the whole year there maintains (维持) above 45℃. But to our great surprise, the tourism (旅游线) there is getting very well. Nearly all the year round the tourists can be seen coming and going.
That is because there are a large number of “In-the-Well Hotels” in Mali. It means that first of all, people have dug a thirty-metre-deep well under very hot land surface, then in the wall of the well several empty caves, about two metres high each, are made. In these caves beds are arranged.
Obviously, In-the-Well Hotel, not as hot as it is out of the well, remains only about 12~20℃. In the cave rooms, tourists can find all the daily necessaries.
It not only frees the guests of the country from the hot weather but also gives them a new and fresh experience. So it is appealing(吸引人的) to the tourists coming all parts of the world.
The best title for this passage should be ________.
A Mali, a Burning Hot Country
B Tourism in Mali
C The Well Hotel
D A way to Develop Tourism
23Imagine life as a game in which you are playing with some five balls in the air. You name them work, family, health, friends and spirit, and you’re keeping all these balls in the air.
You understand that work is a rubber ball. If you drop it, it will bounce back. But the other four balls are made of glass. If you drop one of these, it will be surely marked, broken, damaged or even shattered(粉碎). They will never be the same. You must understand that and strive for balance in your life. How?
Don’t undermine (低估) your worth by comparing yourself to others . It is because we are different that each of us is special. Don’t set your goals by what other people consider important. Only you know what is best for you. Don’t take for granted the things closest to your heart. Stick to them as you would to life, for without them, it’s meaningless. Don’t let life one day at a time, you live ALL the days of your life. Don’t run through life so fast that your forget not only where you’ve been, but also where you’re going. Don’t use time or words carelessly. Neither can be regained. Life is not a race, but a journey to be enjoyed each step of the way. Yesterday is history, tomorrow is a mystery, and today is a gift. That is why we call it---The Present.
Which of the following best states the main idea of the passage?
A We should strive for balance in our life.
B We should not undermine our worth by comparing ourselves to others
C We should not set our goals by what other people consider important.
D Words and time will never return once they are gone.
24Some people think they have an answer to the problems of automobile crowding and pollution in large cities. Their answer is the bicycle, or “bike”.
In a great many cities, hundreds of people ride bicycles to work everyday. In New York City, some bike riders have even formed a group called Bike fie a Better City. They claim that if more people rode bicycles to work there would be fewer automobiles in the downtown section of the city and therefore less dirty air from car engines.
For several years this group has been trying to get the city government to help bicycle riders. For example, they want the city to paint special lanes –for bicycles only—on some of the main streets, because when bicycle riders must use the same lanes as cars, there may be accidents. Bike foe a Better City feels that if there were special lanes, more people would use bikes.
But no bicycle lanes have been painted yet. Not everyone thinks it is a good idea. Taxi drivers don’t like the idea—they say it will slow traffic. Some store owners on the main streets don’t like the idea—they say if there is less traffic, they will have less business. And most people live too far from downtown to travel by bike.
The government has not yet decided what to do. It wants to keep everyone happy. On weekends, Central Park---the largest open space in New York –is closed to cars, and the roads may be used by bicycles only. But Bike for a Better City says that this is not enough and keeps fighting to get bicycle lanes downtown. Until that happens, the safest place to bicycles may be in the park.
The main idea of the passage is to show_________.
A the problems of automobile crowding and pollution in large city,
B bike for a Better City’s answer to the problems of automobiles
C a great many bike riders in New York City.
D the city government’s decision about bicycle lanes.
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