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“Yes, ladies and gentlemen, welcome aboard NASA’s Space Elevator. We’re going to leave soon. The entire ride will take about five hours, so sit back and enjoy the trip. As we rise, be sure to look out the window. You’ll see the sky change from deep blue to black. It is one of the most wonderful views(景色)you will ever see! ”
Does this sound like the Sci-Fi Channel? Well, it’s not. Scientists are thinking that a “space elevator” will be possible toward the end of the 21st century. A space elevator will consist of a long cable (电缆) from the Earth’s surface into space to an altitude(高度) of about 35,786 km. “Elevators” will travel along the cable and move people and loads between Earth and space. One of the greatest advantages is that the cost will be much less. Researchers estimate (估计) that a passenger with baggage at 150 kg might cost only $222! Compare that to today’s cost of around $3.3 million for the same weight. It would make “cheap” space travel possible. Scientists believe carbon nanotubes (纳米管) may be used to make high-strength materials for the cables, although they are still being studied.
It was Arthur C. Clarke who brought this idea to the general public. In his science fiction novel Fountains of Paradise, engineers build a space elevator on top of a mountain peak on an island. One day, Clarke was asked a question by a student during his speech. The student asked when the space elevator would become a reality. Clarke answered, “Probably about 50 years after everybody stops laughing.” He’s got a point. When we stop thinking of something as impossible, then we start working on its development.
小题1:Why should passengers in a space elevator look out the window while they are moving into space?
| A.Because the blue sky is very beautiful. |
| B.Because the view outside is wonderful. |
| C.Because the sky changes from black to blue. |
| D.Because the trip will take about seven hours. |
| A.Scientists haven’t used carbon nanotubes to make the cables. |
| B.Traveling in space elevators will cost much less in the future. |
| C.Passengers will be able to travel in space elevators with baggage. |
| D.Space elevators will travel for 35,786 km around the Earth’s surface. |
| A.Possible Now: Space Travel | B.Cheap Space Travel |
| C.Going into Space in an Elevator | D.Space Travel — Impossible |
根据下列句子及所给单词的首字母写出所缺单词。在填写答卷时,要求写出完整单词。 (每空限填一词)
【小题1】He is very smart.He went to university at the a of 15.
【小题2】Never cross the street when the traffic lights are r .Wait until it’s green.
【小题3】It doesn’t look like rain,so you needn’t b your umbrella with you.
【小题4】I miss my family and really feel l without any friends in this new city.
【小题5】Where is my watch?I can’t f it.
(T="True," F = False)
What is color? Why do some of the things around us look red, some green, others blue?
Colors are really made by reflected(反射) light. We can see colors because most of the things reflect light. Something is red, for it reflects most of the red light. In the same way, if something is green, it reflects most of the green light. If something reflects all light, it is white. If it doesn't reflect any light, it is black.
Some light is reflected. But the other light is taken in and turns into heat. The darker the color is, the less light is reflected, and the more light is taken in. For this reason, dark-colored clothes are warmer in the sun than light-colored clothes.
【小题1】Colors are made by reflected light
【小题2】 Something looks white because it reflects all kinds of light.
【小题3】In the dark we can't see anything because all the things don't reflect any light
【小题4】 When the other light is taken in, it will be reflected in the end.
【小题5】In the sun, the warmest clothes must be light-colored. 查看习题详情和答案>>
The word“day”has two meanings. When we talk about the number of days in a year, we are using“day”to mean 24 hours. But when we talk about day and night, we are using“day”to mean the time between sunrise and sunset. Since the earth looks like a ball, the sun can shine on only half of it at a time. Always one half of the earth is having day and the other half night. A place is moved from day into night and from night into day over and over by the spinning(旋转)of the earth. At the equator(赤道)day and night are sometimes the same length(长度). They are each twelve hours long. The sun rises at 6 o’clock in the morning and sets at 6 o’clock in the evening. For six months the North Pole is tilted(倾斜)toward the sun. In those months the Northern Hemisphere(半球)gets more hours of sunlight than the Southern Hemisphere. Days are longer than nights. South of the equator nights are longer than days. For the other six months the North Pole is tilted away from the sun. Then the Southern Hemisphere gets more sunlight. Days are longer than nights. North of the equator nights are longer than days. Winter is the season of long nights. Summer is the season of long days.
【小题1】A place is moved from day into night and from night into day over and over by ____ of the earth.
| A.the pushing | B.the pulling | C.the spinning | D.the passing |
| A.sometimes | B.never | C.usually | D.always |
| A.less | B.more | C.all | D.no |
What is your favorite color? Do you like yellow, orange, or red? If you do, you must be an active person who enjoys life. Do you like blue? Then you are probably quiet, shy, and would rather follow than lead.
Colors do influence our moods (情绪). A yellow room makes most people feel more cheerful and more relaxed than a dark green one; and a red dress brings warmth and cheer to the saddest winter day. On the other hand, black is depressing(令人压抑的). There was a black bridge over the Thames River, near London. The number of people who killed themselves on that bridge used to be larger than on any other bridge in the area -- until it was repainted green.[来
Light and bright colors make people not only happier but also more active. In the factory, the workers will work better, harder, and have fewer accidents when their machines are painted orange rather than black.
【小题1】 An active person may like
| A.yellow, orange, or red | B.yellow, black, or red |
| C.orange, blue, or black | D.black, red, or orange |
| A.tired | B.bored | C.worried | D.relaxed |
| A.the bridge was very tall | B.the bridge was too crowded |
| C.people didn’t like the bridge | D.the color of the bridge was depressing |
| A.worse | B.harder | C.more slowly | D.more angrily |
| A.Cheerful Colors | B.Your Favorite Color |
| C.The Secret of Color | D.The Color of a Bridge |