The surprising experiment I am about to describe proves that air is all around
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The surprising experiment I am about to describe proves that air is all around you and that it presses down upon you. Air pressure is a powerful force. When you swim underwater, you can feel water pushing down on your body. The air all around you does the same. However, your body is so used to it that you do not notice this. The pressure is caused by a layer of air called the atmosphere. This layer surrounds the Earth, extending to about five kilometers above the Earth’s surface.
The following experiment is an easy one that you can do at home. But make sure that you are supervised, because you will need to use matches. Now for the experiment！
What you need
•A hard-boiled egg without the shell
•A bottle with a neck slightly smaller than the egg
•A piece of paper
•A match
Method
1） Check that the egg will sit firmly on the neck of the bottle.
2） Tear the paper into strips and put the strips into the bottle.
3） Light the paper by dropping a burning match into the bottle.
4） Quickly sit the egg on the neck of the bottle.
Result
Astonishingly, the egg will be sucked into the bottle. Your friends will be amazed when you show them the experiment. But be careful when you handle matches.
Why it happened
As the paper burns, it needs oxygen and uses up the oxygen （air） in the bottle. The egg acts as a seal in the neck of the bottle, so no more air can get inside. This reduces the air pressure inside the bottle. The air pressure must equalize, so more air from outside must enter the bottle. The outside air pressure against the egg and then the egg is pushed into the bottle! This proves that air is all around and that it is pressing down on it.
小题1:Why is there the need to take care when you are doing the experiment? | A．The bottle could break. | | B．You need to light the paper with a match. | | C．The egg needs to be shelled. | | D．The egg has to be perfectly placed on the neck of the bottle. |
小题2:In the experiment, the burning inside the bottle can___. | A．equalize the air pressure inside and outside | | B．make a seal in the neck of the bottle | | C．finish up the oxygen inside the bottle | | D．produce more oxygen inside the bottle |
小题3:How did the egg put into the bottle？| A．The oxygen inside the bottle sucked the egg in. | | B．It became saft without the shell. | | C．The neck of the bottle was wide enough. | | D．The outside air pressure forced it into the bottle. |
小题4:The experiment is carried cut to prove ______. | A．water pushes on your body when you swim underwater. | | B．the earth is surrounded by a layer of air called the atmosphere. | | C．the pressure of air around us has a powerful force. | | D．the air pressure is not equalized around us. |
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答案
小题1:B
小题2:C
小题3:D
小题4:C |
解析
小题1:细节理解。根据第二段的内容可知在做实验的过程中要小心，因为需要使用火柴，由此可知B项是正确的。
小题2:细节理解。根据第一段第一句中的内容可知瓶内有燃烧可以耗尽里面的氧气。
小题3:细节理解。根据最后一段到数第二句中的内容可知，鸡蛋是在瓶外空气的压力下掉入瓶中的。
小题4:推理判断。结合第一段中的Air pressure is a powerful force和最后一段最后一句的内容可以推知这实验的目的是证明我们周围的空气具有很大的压力。 |
举一反三
New archaeological discovers suggest that trade between Europe and Asia along the Silk
Road probably began in some form many countries earlier than once thought. The findings, coupled with a widening range of scientific and historical research, could add a fascinating new
page to the epic of the Silk Road.
The latest and most surprising discovery is pieces of silk found in the hair of an Egyptian mummy from about 1000 BC, long before regular traffic on the Silk Road and at least one thousand years before silk was previously thought to be used in Egypt. Other research may extend human activity along this route back even further, perhaps a million years to the migration of human ancestors into eastern Asia.
The official origin of East-West commerce along the road is usually placed in the late 2nd century BC when an agent of the Chinese Emperor Wu-di returned from a dangerous secret mission（使命）across the desert into the remote high country of Central Asia. The agent, Zhang Qian, travelled as far as Afghanistan and brought back knowledge of even more distant lands such as Persia, Syria and a place known as Lijien, perhaps Rome. Historians have called this one of the most important journeys in ancient times. His journey opened the way for what have been thought to be the first indirect contacts between the ancient world’s two superpowers, China and Rome. Chinese silk, first traded to central Asian tribes for war horses and to the Parthians of old Persia in exchange for acrobats and ostrich eggs, was soon finding its way through a network of merchants to the luxury markets of Rome.
But the new discoveries show that Chinese silk was apparently present in the West long before the Han emperor started organized trade over the Silk Road. The research could change thinking about the early history of world trade and provide insights into the mystery of just how and when Europe and the Mediterranean lands first became aware of the glorious culture at the other end of Eurasia.
小题1:The word “coupled” in the first paragraph could best be replaced by ______. | A．produced | B．contributed | C．doubled | D．combined |
小题2:The silk thread found in the hair of an Egyptian mummy suggests that ______. | A．Egyptians had probably travelled to China to buy silk | | B．trade along the Silk Road began earlier than once thought | | C．historical research often achieves fascinating results | | D．new light can now be thrown on ancient trading practices |
小题3: Until recently most historians believed that trade along the Silk Road _______. | A．originated in the 2nd century BC | | B．extended human migration into eastern Asia | | C．began a million years ago | | D．primarily benefited the Egyptians |
小题4:Historians have always considered Zhang Qian’s mission important because they believe ______. | A．be brought back knowledge of Rome to the emperor | B．be discovered the Silk Road | | C．be helped establish East-West trade | D．be travelled as far as Afghanistan |
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E
Most of us are used to seasons. Each year, spring follows winter, which follows autumn, which follows summer, which follows spring. And winter is colder than summer. But the earth goes through temperature cycles over much longer periods than those that we experience.
Between 65,000 and 35,000 years ago, the planet was much colder than it is now. During that time the temperature also changed a lot, with periods of warming and cooling. Ice melted during the warm periods, which made sea levels rise. Water froze again during the cold periods.
A new study from Switzerland sheds light on where ice sheets melted during the ice age.
It now seems that the ice melted at both ends of the earth, rather than just in either northern or southern areas. This surprised the researchers from the University of Bern.
Scientists have long assumed(认为) that most of the ice that melted was in the Northern hemisphere(半球) during the 30,000-year-long ice age. That belief was held because the North Pole is surrounded by land, while the South Pole is surrounded by theAntarctic Ocean. It is easier for ice sheets to grow on land. If surrounded by sea, the ice can easily just slip to the ocean instead of building up.
The researchers used a computer model to look at the ways the ice could melt and how it might affect sea levels. They compared these results to evidence(迹象) of how temperatures and currents actually changed during that time.
The model showed that if it was only in the Northern hemisphere that ice melted, there would be a bigger effect on ocean currents(洋流) and sea temperatures than what actually happened. Studies suggest that melting just in the Southern hemisphere would have been impossible, too.
The only reasonable conclusion, the scientists could make, was that the ice melted equally in the North and the South.
It is still a mystery(谜) as to what caused the temperature changes that caused the ice to melt.
72. We can learn from the text that _____.
A.we have experienced temperature cycles since they began
B.what caused ice to melt is still unknown
C. the planet was much colder than it is now between 65,000 and 35,000 years ago, during which time temperature hardly changed
D. before the new study, scientists long believed that ice melted just in either northern or southern areas
73. The underlined phrase "sheds light on" （in Paragraph 3） can be replaced by _____.
A. throws doubts on B. beats down on C. makes it clear D. makes light of
74. The first two paragraphs were written _____.
A. to lead up to the subject that ice melted during the 30,000-year-long ice age
B. to describe what the weather was like during the ice age
C. to compare climate nowadays with that of the ice age
D. to explain what a temperature cycle is
75. Which of the following best shows the relationship between ice, ocean currents and temperatures according to the text?
A. Ice can easily slip into the ocean.
B. Temperature and currents changed as a result of ice melting.
C. Temperature changes lead to ice melting or water freezing, which in turn has an effect on ocean currents and temperature.
D. Ice melted and then froze again due to temperature. |
Think of London and you’re likely to think of the city’s famous bright red double-decker(双层) buses．Think of Thailand’s capital city, Bangkok，and the noisy tuk-tuk(三轮摩托车) may come to mind．Picture the American city of San Francisco and you might see the city’s cable cars(电车)．
Imagining what these cities would look like without their red buses，tuk-tuks or cable cars is difficult．They are symbols of these cities that make them different from anywhere else in the world．However,these city symbols，which are so 1oved by tourists，are not always so well loved by their city 1eaders． City 1eaders want what is best for their city, which often means the most modern transport．
In Thailand，Bangkok city authorities have forbidden new tuk-tuks because they consider them noisy and polluting．However, the ban has largely been unsuccessful，as it has not changed Thai people’s preference for the inexpensive tuk-tuks over taxis．
In London，the city’s first ever mayor got rid of the red double-decker buses． which he thought were old—fashioned, by selling them to other countries．His plan worked．but Londoners were upset to lose the charming old buses that they believed represented the best of their city. They made their upset felt， when the mayor came up for re-election 1ast year．Most Londoners voted for his competitor, who promised to bring the bus back．Now, an improved version(版本)of the double-decker bus will hit London’s streets in 2012．
AS for San Francisco, several cable cars remain in use but mainly as tourist attractions．They are too slow to be used for anything other than scenic trips．
City transport symbols may have palace in their city people’s hearts，but it seems they are increasingly out of step with the modern world．As Londoners have proved，their continued 1ife depends on people’s willingness to fight for their survival．
5．What’s the purpose of writing the first paragraph?
A．To show the cultural significance of several cities’unique transport systems．
B．To introduce some old-fashioned means of transport, which are symbols of three tourist cities．
C．To use the old transport symbols to attract more tourists to visit the cities．
D．To explain why those cities are popular with tourists around the world．
6．Bangkok’s ban on tuk-tuks is unsuccessful due to ________.
A．people’s unawareness of environmental protection
B．tourists’preference for tuk-tuks over taxis
C. the lack of severe punishment for violation
D．1ocals’willingness to take the tuk-tuks
7．The London double Decker bus is returning mainly because______.
A．it is an improved version B．The new mayor also loves it
C. it is popular with tourists D．Londoners fought for it
8．Which example can prove old city transport symbols are not loved by city leaders?
A．Bangkok city authorities tried to get rid of the cheap tuk-tuks．
B．The mayor who sold double-decker buses lost the re-election．
C．The new mayor will bring back improved double-decker buses．
D．Only a few cable cars remain in use by tourists in San Francisco．
9．We can conclude from reading the passage that_______.
A．Tourist cities will lose their charm if their old transport symbols disappear
B．A modern city should get rid of inefficient old transport
C．Old city transport symbols now face the problem of survival
D．The writer is in favor of keeping the old city transport symbols |
I had my first job at the age of thirteen, when a friend of my mother’s who owned a book shop 36 me for six hours a week to help her in the shop. I was very 37 to earn my own pocket money and my parents 38 interfered with how I spent it, even when I was spending it 39 . They believed that by earning money, spending it, and learning from the 40 , I would become more mature and 41 about how to handle work, relationships with others, and money.
Like many 42 parents, my parents also let me and my brothers do things over which they 43 a great deal. When I was sixteen, for example, after I finished high school and before I entered university, I wanted to spend the summer months traveling around 44 . My mother was against the idea of my traveling alone at such a young age, but my father felt that it would be a great 45 for me. In the end, my father won the 46 on the condition that I limited my traveling to France, my mother’s home, where I had many uncles, aunts and cousins 47 through the country who could 48 shelter and help if I needed them.
Three years later, my younger brother decided to 49 a year off after his first year in university and travel through the United States and the Caribbean. Again my mother was very worried and not 50 to see my brother leave school, but my father encouraged him and my brother had a(n) 51 year working his way on trains and ships to 52 passage to different ports and cities, and discovering many fascinating places and people.
These kinds of experiences are probably rare for children in many countries but in the US they are fairly 53 . Most parents start 54 their children at a young age to do small things by themselves. By the time they have finished high school, many American kids have already had part-time jobs, traveled around the US or other countries on their own, have 55 the university they plan to attend and maybe even decided on their future career, and so on.
36. A. taught B. allowed C. treated D. hired
37. A. anxious B. content C. proud D. hopeful
38. A. never B. ever C. always D. even
39. A. quickly B. foolishly C. seriously D. honestly
40. A. work B. mistakes C. others D. books
41. A. strict B. reasonable C. polite D. responsible
42. A. American B. Japanese C. Chinese D. British
43. A. helped B. supported C. shared D. worried
44. A. Asia B. Africa C. Europe D. Oceania
45. A. journey B. experience C. chance D. possibility
46. A. argument B. game C. discussion D. plan
47. A. send out B. give out C. carry out D. spread out
48. A. promise B. afford C. provide D. serve
49. A. leave B. make C. take D. prepare
50. A. angry B. eager C. sorry D. sad
51. A. unusual B. hard C. strange D. busy
52. A. accept B. earn C. find D. search
53. A. welcome B. fit C. necessary D. common
54. A. bringing B. forcing C. pushing D. protecting
55. A. selected B. admired C. afforded D. left |
Stepping into a pool of water is common enough, but who could ever imagine stepping into a pool of fish? In February of 1974, Bill Tapp, an Australian farmer, saw a rain of fish that covered his farm. How surprised he must have been when he heard many fish hitting against his roof!
What caused this strange occurrence? This is a question that had long puzzled people who study fish. The answer turned out to be a combination of wind and storm.
When it is spring in the northern part of the world, it is fall in Australia. Throughout the autumn season, terrible storms arise and rains flood the land. The strong winds sweep over Australia like huge vacuum cleaners, collecting seaweed, pieces of wood, and even schools of fish. Strong winds may carry these bits of nature for many miles before dropping them on fields, houses, and astonished people.
Although they seem unusual, fish-falls occur quite frequently in Australia. When Bill Tapp was asked to describe the scene of fish, he remarked, “They look like millions of dead birds falling down.” His statement is not surprising. The wonders of the natural world are as common as rain. Nature, with its infinite wonders, can create waterfalls that flow upward and fish that fall out of the sky.
56. What is this passage about?
A. A sad story. B. A rain of fish.
C. Australia’s northern part. D. The damage done by floods.
57. Fish-falls occur in Australia_________ .
A. quite often B. on large farms
C. only in winter D. when the air is calm
58. It is a known fact that ________.
A. one should watch where one steps
B. Bill Tapp is a scientist who studies farming
C. the natural world can never create waterfalls that fall upward
D. the seasons in the southern part are different from those in the northern part
59. The word “infinite” is closest in meaning to _________.
A. easy B. difficult C. countless D. dangerous |
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