题目内容
When many people see birds cleaning their feathers, they attribute it to vanity on the part of the bird. But, in reality, what they are doing is maintaining their wings, the instruments that they depend on for safe flight. If a bird’s wings are not in perfect condition, the bird either won’t be able to fly or won’t be able to control its flight. That is why after a long flight and even throughout the day, you will see them cleaning their feathers.
Most birds, if they get a chance, will take a bath at least once a day. They do this to get rid of the dust that has accumulated in their feathers throughout their flight s during the day. In dry or desert areas, birds will not always be able to find water in which to bath, but they still need to clean their feathers. What many birds will do is to take dust baths. They will roll around in dust until it covers their feathers. They will stand up, shaking the dust out, and then clean their feathers with their beaks (鸟嘴) as usual.
Baths are important for another reason. During the course of the day and night, many parasites (寄生虫) are attracted to birds. Bugs, mites, fleas and so on will try to reach birds and suck from their blood. Daily baths help to keep the parasites to a minimum.
Some birds, especially those that spend a lot of time in or around water, have skin glands (皮肤腺) that produce oil. After bathing, these birds will squeeze the glands to spread the oil over their wings to keep them free of water.
If you are a bird lover and have bird houses in your yard, it can be good to go to the extra step, providing a bird bath. Once the birds in your neighborhood discover it, you will be surprised at how popular it becomes as they periodically stop by to take their daily bath.
【小题1】What’s the passage mainly about?
| A．How birds clean themselves. | B．What birds enjoy doing. |
| C．Why baths matter so much to birds. | D．What bird lovers should do. |
| A．Most people think it good for birds to clean their feathers. |
| B．Most people show much interest in how birds clean themselves. |
| C．Most people believe that birds’ keeping themselves clean is necessary. |
| D．Most people think birds’ cleaning their feathers of no practical significance. |
| A．helps keep them healthy | B．keeps them free of any parasite |
| C．makes them more attractive | D．helps them relax enough |
| A．we should love birds as much as possible |
| B．birds enjoy cleaning themselves by bathing |
| C．we can be good bird lovers by bathing birds |
| D．birds like to come close to the people in a yard |
【小题1】C
【小题2】B
【小题3】A
【小题4】A
解析
Since the 1950s, most of the stars of pop music have come from Britain and America. Howver, in the last ten years, when many different kinds of music have established themselves on the pop scene, more and more stars have come from other countries.
Pop music changes all the time and new stars appear and become famous. For a musician to stay popular and still produced good, original music over a long period of time, is a sign of true star.
Most stars start their careers in a simple way---- playing in unknown night clubs or dance-hall where people want to dance to the music, not listen to it. They may have continued doing this for many years untill they get a “break”---- a chance to perform in a well –known place or get a recording contract. To become a star is the aim of every singer or musician and the dream of many a pop-crazy teenager.
However a group or star makes it to the top, they can be sure that their lives will change once they are successful. Ordinary teenagers living at home with their parents may suddenly find themselves rich enough to buy their own houses. An established superstar may be able to buy several.
Despite the large amount of money that are earned, life at the top is not easy for many stars.. The pop scene is hard work and many stars need to spend a lot of time away from home. For a lot of them, this means they have no home life and their personal relationships suffer. Despite great public success, life at the top can be very lonely.
【小题1】Since the 1950s,most of the stars of pop music have come from______.
| A．America | B．America and Britain |
| C．America and Europe | D．other countries |
| A．perform in a well-known concert | B．get a recording contract |
| C．play in dance-halls | D．meet a lot of pop-crazy teenagers |
| A．will live at home with their parents |
| B．will have an easy life because of the larger amount of money earned |
| C．may have a happy home life and good person relationships |
| D．may have a lonely life |
For years, the automobile industry has been testing vehicles that use hydrogen as fuel. Now, people across the United States have had a chance to see and even drive cars that get power from hydrogen fuel cells (燃料电池).
But the hydrogen fuel cell is not a new idea. The fuel cell was first invented by Sir William Grove of Britain in 1839. Since then, many different designs, have been invented. There is one place where fuel cells are a proven technology: in space. The American space agency used fuel cells in its Apollo spaceships in the twentieth century.
The most useful fuel cell for transportation purposes is the Polymer Electrolyte Membrane, or P.E.M. fuel cell. It is simple and can operate at temperatures of sixty to eighty degrees Celsius. That is much lower than other fuel cell designs. A P.E.M. fuel cell has two sides divided by a thin membrane (膜). Hydrogen gas is forced through one side where it comes in contact with a reactive material containing the metal platinum(铂). The membrane separates the electrons(电子) from the protons(质子) in the hydrogen atoms. The protons pass through it to the other side of the fuel cell. But the electrons are captured to do work; like powering a motor. Oxygen from the air is forced into the other side of the fuel cell. There, the gas meets the protons that have passed through the membrane. They combine to form water and heat. A single fuel cell does not produce a lot of electricity. But when many fuel cells are combined, they can produce enough electricity to power a vehicle. The product of the chemical reaction that powers fuel cells is water. This makes fuel cells a very clean technology.
Hydrogen fuel cell cars have been slow to develop because of many technical problems that have to be solved. For example, it is unclear how long the membranes in P.E.M. fuel cells will last. Also, fuel cells need water for their chemical reactions. They must be designed to start easily at low temperatures and in dry climates. And smaller, less costly fuel cells must be designed before they can truly take the place of gasoline engines. Now more models of fuel cell vehicles are being tested than ever before. The threat of climate change and the high cost of oil have increased interest in these vehicles that do not cause pollution.
|
Title |
More Models of Hydrogen Cars Being Tested |
|
The progress of hydrogen fuel cell |
·(1) ________ by Sir William Grove in 1839. ·Designed (2) ________ ever since. ·Used in Apollo spaceships in the twentieth century. |
|
Operating principle of P.E.M. |
·It has two sides divided by a thin membrane. ·Hydrogen gas from one side (3) ________ the active metal platinum. ·The electrons are (4) ________ from the protons in the hydrogen atoms. ·The protons pass through the fuel cell to the other side. ·Oxygen from the air is (5) ________ into the other side of the fuel cell. ·The gas meets the protons，and then water and heat are(6) ________ |
|
Reasons for slow (7) ________of hydrogen fuel cell cars |
·There are many technical problems (8) ________ ·The durability of the membranes in P.E.M. fuel cells is not clear. ·They have to start easily at (9)________ temperatures and in dry climates. ·They must be smaller and less costly before (10) ________ gasoline engines. |
