AcatisrecoveringinCaliforniaaf-优题课

Unless we spend money spotting and preventing asteroids(小行星) now, one might crash into Early and destroy life as we know it, say some scientists.
Asteroids are bigger versions of the meteoroids(流星) that race across the night sky. Most orbit the sun far from Earth and don’t threaten us. But there are also thousands of asteroids whose orbits put them on a collision course with Earth.
Buy $50 million worth of new telescopes right now. Then spend $10 million a year for the next 25 years to locate most of the space rocks. By the time we spot a fatal one, the scientists say, we’ll have a way to change its course.
Some scientists favor pushing asteroids off course with nuclear weapons. But the cost wouldn’t be cheap. Is is worth it? Two things experts consider when judging any risk are: (1)How likely the event is; and (2) How bad the consequences if the event occurs. Experts think an asteroid big enough to destroy lots of life might strike Earth once every 500 000 years. Sounds pretty rare-but if one did fall, it would be the end of the world. “If we don’t take care of these asteroids, they’ll take care of us,”says one scientist. “It’s that simple.”
The cure, though, might be worse than the disease. Do we really want fleets of nuclear weapons sitting around on Earth? “The world has less to fear from doomsday(世界末日) rocks than from a great nuclear fleet set against it,” said a New York Times article.
9.What does the passage say about asteroids and meteoroids?
A.They are heavenly bodies different in composition.
B.They are heavenly bodies similar in nature.
C.There are more asteroids than meteoroids.
D.Asteroids are more mysterious than meteoroids.
10.What do scientists say about the collision of an asteroid with Earth?
A.It is very unlikely but the danger exists.
B.Such a collision might occur once every 25 years.
C.Coilisions of smaller asteroids with Earth occur more often than expected.
D.lt’s still too early to say whether such a collision might occur.
11.What do people think of the suggestion of using nuclear weapons to alter the course of asteroids?
A.It sounds practical but it may not solve the problem.
B.It may create more problems than it might slove.
C.It is a waste of money because a collision of asteroids with Earth is very unlikely.
D.Further research should be done before it is proved applicable.
12.We can conclude from the passage that .
A.while pushing asteroids off course nuclear weapons would destroy the world
B.asteroids racing across the night sky are likely to hit Earth in the near future
C.the worry about asteroids can be left to future generations since it is unlike to happen in our lifetime.
D.workable solutions still have to be found to prevent a collision of asteroids with Earth

America is a country on the move. In unheardof numbers, people of all ages are exercising their way to better health. According to the latest figures, 4 percent of American adults exercise regularly-up 12 percent from just two years ago and more than double the figure of 25 years ago. Even non-exercisers believe they would be more attractive and confident if they were more active.
It is hard not to get the message. The virtues of physical fitness are shown on magazine covers, postage stamps, and television ads of everything from beauty soaps to travel books. Exercise as a part of daily life did not catch on until the late 195s when research by military doctors began to show the health benefits of doing regular physical exercises. Growing publicity (宣传) for races held in American cities helped fuel a strong interest in the ancient sport of running. Although running has leveled off in recent years as Americans have discovered equally rewarding-and sometimes safer-forms of exercise, such as walking and swimming, running remains the most popular form of exercise.
As the popularity of exercise continues to mount, so does scientific evidence of its health benefits. The key to fitness is exercising the major muscle groups vigorously (强有力地) enough to approximately double the heart rate and keep it doubled for 20 to 30 minutes at a time. Doing such physical exercises three times or more a week will produce considerable improvements in physical health in about three months.
5.It can be learnt from the passage that the health benefits of exercise .
A.are to be further studied B.are selfevident
C.are yet to be proved D.are supported by scientific evidence
6.A growing interest in sports developed after___________ .
A.an increasing number of races were held in American cities
B.research showed their health benefits
C.scientific evidence of health benefits was shown on TV ads
D.people got the message from magazine covers and postage stamps
7.Which of the following would be the best title for the passage?
A.Exercise-The Road to Health B.Scientific Evidence of Health Benefits
C.Different Forms of Exercise D.Running-A Popular Form of Sport
8.Which of the following is closest in meaning to the phrase “leveled off” in the paragraph 2?
A.“reached its lowest level in popularity” B.“stopped being popular”
C.“stopped increasing in popularity” D.“become very popular”

Even with little exposure to cultural standards of beauty, “infants treat attractive faces as distinctive regardless of the sex, age a nd race of the stimulus(刺激物) faces,” write psychologist Judith H.Langlois and her colleagues in the January DEVELOPMENTAL PSYCHOLOGY.
In their experiment, 5 healthy 6-month-old infants from middle-class families viewed slides showing eight pairs of white male faces and eight pairs of white female faces. Each pair, displayed for 10 seconds, consisted of one attractive and one unattractive face, as previously judged by a group of male and female college students. An experimenter viewed the young participants on a video monitor and recorded the direction and duration of each infant’s gaze.
The 35 boys and 25 girls looked longer at both male and female faces judged as attractive, the researchers found.
Their second study of 6-month-old involved 15 boys and 25 girls, mostly white, who saw eight pairs of slides showing an attractive and an unattractive black female, as previously judged by both white and black college students. Again, the babies looked much longer at attractive faces.
Finally, 19 boys and 20 girls, all 6 months old and almost all of them white, viewed eight pairs of slides showing the faces of 3-month-old boys and girls previously rated as attractive or unattractive by college students. Attractive baby faces drew signficantly longer looks, the psychologists report.
Further studies must explore whether infants take attractive faces as “best examples” of a face, the investigators claim Langlois and a coworker recently reported that attractive faces may possess features that approximate the mathematical average of all faces in particular population.
1.What was found in the first study?
A.Male infants looked longer only at female ones.
B.Females looked more attractive than males.
C.Sixty 6monthold babies looked longer at the attractive faces, male or female.
D.White female faces drew more attention than those of black ones.
2.In the last paragraph, the writer implies that .
A.Langlois and her partners will stop their experiments they accomplished a lot
B.Langlois and her partners will focus on the other fields of infants
C.Langlois and her partners have achieved success in studying the infants’ mind
D.Langlois and her partners have found a more interesting field
3.What can be inferred from the passage?
A.All babies, white or black, tend to share with the college students the preference for attractive faces.
B.White babies prefer white faces to black ones.
C.Babies tend to get interested in the attractive faces of the opposite sex.
D.Beauty has something to do with a person’s age, race and sex
4.The title that best expresses the main idea is .
A.Psychology of Infants B.Beauty in Variety C.Beauty and Race D.Beauty in Infants

A punctual person is in the habit of doing a thing at the proper time and is never late in keeping an appointment.
The unpunctual man, on the other hand, never does what he has to do at the proper time. He is always in a hurry and in the end loses both time and his good name. A lost thing may be found again, but lost time can never be regained. Time is more valuable than material things. In fact, time is life itself. The unpunctual man is for ever wasting and mismanaging his most valuable asset as well as others’. The unpunctual person is always complaining that he finds no time to answer letters, or return calls or keep appointments promptly. But the man who really has a great deal to do is very careful of his time and seldom complains of want of it. He knows that he can not get through huge amount of work unless he faithfully keeps every piece of work when it has to be attended to.
Failure to be punctual in keeping one’s appointments is a sign of disrespect towards others. If a person is invited to dinner and arrives later than the appointed time, he keeps all the other guests waiting for him. Usually this will be regarded as a great disrespect to the host and all other guests present.
Unpunctuality, moreover, is very harmful when it comes to doing one’s duty, whether public or private. Imagine how it would be if those who are put in charge of important tasks failed to be at their proper place at the appointed time. A man who is known to be habitually unpunctual is never trusted by his friends or fellow men.
12. What is an unpunctual person like?
A. He always does a thing when it should be done. B. He is always very busy.
C. He always does a thing at the wrong time. D. He always keeps the appointments.
13. Why is unpunctuality very harmful?
A. Because it makes a man lose many chances of doing important affairs.
B. Because it makes a man lose friends.
C. Because it makes a man work quickly.
D. Because it makes a man be more respected by others.
14. According to the passage, which is right?
A. The punctual person has no much work to do.
B. The unpunctual person is very rich
C. The unpunctual person is often respected by his friends.
D. The unpunctual person loses what can’t be regained again.
15. According to the passage, what are good manners when you are invited to a party?
A. Arriving at the appointed time. B. Arriving before all other guests.
C. Arriving after all other guests. D. Keeping all other guests waiting.
16. Why is a person always unpunctual?
A. He is too busy.B. He has too much work to do.
C. He does care much about time. D. He doesn’t manage his time properly.

Today, ultrasonic(超声的) waves are being put to work in laboratories and factories. If an ultrasound generator is placed in a liquid, the waves move the liquid back and forth hundreds of thousands of times each second. This causes materials to mix quickly or to dissolve(使分解，使溶解) in liquids. Paint manufacturers(制造商) use ultrasound to do a better job of blending colors. The companies that make film for your camera find that mixing chemicals by the use of sound waves will produce a more sensitive film.
The new lightweight(轻量的) type of washing machine uses ultrasonic waves to get clothes clean. Its special ultrasound generator is put into a pail of soapy water containing the soiled clothes. The sound waves drive the soapy water back and forth through the cloth so fast that everything is soon clean. There is also a new kind of dishwasher that works in much the same way.
Ultrasonic waves can shake a liquid so fast that tiny holes form all through it. The liquid is actually torn apart by this action. Almost as soon as these holes are made, they fall together again. The result is a powerful pounding action. In the dairy industry this is used for the double purpose of making homogenized(使均匀，使匀质) milk and sterilizing(使无菌) it at the same time. If you look at some raw milk with a microscope, you find that it is made up of little drops of butter fat floating around in a watery liquid. In order to make milk easier to digest, these fat droplets(微粒) may be broken up by forcing the milk through very small openings. The result is called homogenized milk. When the ultrasonic method is used, the sound waves not only break up the droplets but also kill the germs in the milk by pounding them to pieces. (from www.nmet84.com)
8. Why does a paint manufacturer use ultrasound to do a better job of blending colors?
A. Because it is cheap to use ultrasound to blend colors.
B. Because the waves move the liquid so quickly that it can make materials mix quickly or dissolve in liquids.
C. Because they can mix chemicals by the use of sound waves.
D. Because the waves can clean the paint.
9. What properties does ultrasound wave have?
A. Homogenizes and sterilizes the milk. B. Mix materials and break droplets.
C. Kill germs and sterilize milk. D. Move liquids quickly.
10. What exists in the raw milk?
A. Little drops of butter fat. B. Small holes. C. Fat droplets and germs. D. Chemicals.
11. Where is ultrasound wave not used?
A. In the paint manufacture. B. In the shop mixing bread flour.
C. In the film-making company. D. In the dairy industry.