Air, l , and solid are the three states of objects. 查看更多

 

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C
Wind is the movement of air from an area of high pressure to an area of low pressure. In fact, wind exists because the sun unequally heats the surface of the Earth. As hot air rises, cooler air moves in to fill the gap. As long as the sun shines, the wind will blow. And as long as the wind blows, people will manage it to power their lives.
Ancient sailors used sails to capture the wind and explore the world. Farmers once used windmills to grind their grains and pump water. Today, more and more people are using wind turbines to make electricity from the breeze. Over the past decade, wind turbine use has increased at more than 25 percent a year. Still, it only provides a small part of the world's energy.
Most wind energy comes from turbines that can be as tall as a 20-story building and have three 200-foot-long (60-meter-long) blades. These devices look like giant airplane propellers(螺桨)on a stick. The wind spins the blades, which turn a shaft connected to a generator.
The biggest wind turbines generate enough electricity to supply about 600 U.S. homes. Wind farms have tens and sometimes hundreds of these turbines lined up together in particularly windy spots, like along a ridge. Smaller turbines set up in a backyard can produce enough electricity for a single home or small business.
Wind is a clean source of renewable energy that produces no air or water pollution. And since the wind is free, operational costs are nearly zero once a turbine is erected. Mass production and technology advances are making turbines cheaper, and many governments decrease tax to encourage wind-energy development.
Some people think wind turbines are ugly and complain about the noise the machines make. The slowly rotating blades(螺旋风片) can also kill birds and bats, but not nearly as many as cars, power lines, and high-rise buildings do. The wind is also changeable: If it's not blowing, there's no electricity generated.
Nevertheless, the wind energy industry is increasing sharply. Globally, generation more than quadrupled(四倍) between 2000 and 2006. At the end of last year, global capacity was more than 70,000 megawatts. In the energy-hungry United States, a single megawatt is enough electricity to power about 250 homes. Germany has the most installed wind energy capacity, followed by Spain, the United States, India, and Denmark. Development is also fast growing in France and China.
Industry experts predict that if this pace of growth continues, by 2050 the answer to one third of the world's electricity needs will be found blowing in the wind
63. According to the passage, which of the following statements is true?
A. The rotating blades can kill as many birds as high-rise buildings do
B. Single families are not encouraged to build turbines.
C. The USA produces more wind power than any other country in the world.
D. The noise the turbines make may discourage people from building them.
64. The underlined word “generator” in the third paragraph probably means_______.
A. 电动机                 B. 发电机                    C. 机翼                       D. 飞机引擎
65. If the USA wants to build wind turbines in an area with 30,000 homes, how many
should they build at least?
A. 50.                          B. 150.                         C. 250.                         D. 200.
66. All the following are the advantages of wind energy EXCEPT that_________.
A. it is environmentally friendly                        B. it is free to build and operate
C. the government supports it                                   D. the energy is clean and renewable

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    As bananas ripen, the green skin turns ye11ow gradually. Chemical changes occur in the f1esh of the fruit as well:starch(淀粉)changes to sugar;pectin(果胶)breaks down,losing its stiffness; and the f1esh softens.
Is ripening fruit a self-contained system, or is the rate of these changes affected by the environment? We designed the experiment below to see if different atmospheres, produced by different packaging, affected the rate of ripening. You will vary the atmosphere surrounding unripe bananas and observe the effect on the ripening process。
Now set up the bananas in their environments as follows:
1. Put two green bananas in a paper bag and fo1d the top over to seal out the air.
2.Put one green banana and the very ripe banana in the other paper bag and fold over the top.
3. Put two green bananas in a plastic bag and seal it.
4. Wrap(包)one green banana tightly in a plastic bag.
5. Leave one green banana exposed to the air.
Leave the fruit a1one or five days to ripen. Ripening fruit“breathes”. This means that it takes up oxygen and gives off C02. Oxygen is extremely important and necessary for the chemical reactions involved in ripening. In addition, ripening fruit gives off another gas, called ethylene(乙烯). Not only is ethylene a product of ripening fruit, it also promotes the further ripening of the fruit.
Paper bags tend to keep the ethylene in, but they allow oxygen and ethylene to pass through slowly. Plastic bags do not allow the free flow of oxygen or ethylene. In this experiment, the green banana in paper bag with the ripe banana should ripen most quickly. The green bananas in the paper bag should ripen faster than the bananas in the plastic bag. The banana left exposed to air has an unlimited supply of oxygen, so it will turn brown most quickly. You will notice that the side of this banana that rests on the counter will ripen more quickly than the other sides, because it has the
closest contact(接触)with its own ethylene. The banana that is tightly wrapped in plastic has no oxygen supply and should ripen most slowly. Now can you see why bananas are sealed in plastic in many supermarkets?
72. What makes the green banana in Bag 2 ripen more quickly than the ones in Bag 1?
A. Ethylene from the very ripe banana.            B. The free flow of oxygen or ethylene
C. C02 from the very ripe banana.                     D. The limitation of oxygen supply.
73. How can we slow down the ripening of bananas exposed to the air?
A. To rest them on the counter.                                   B. To keep them in the basket.
C. To put them on the ground.                                     D. To hang them up from the ceiling
74. It can be concluded from the passage that          .
A. the ripening banana is a self-contained system
B. the rate of ripening bananas is affected by the environment
C. wrapped bananas experience no chemical changes to ripen
D. ripening bananas give off oxygen, C0, and ethylene
75. Why are bananas sealed in plastic in many supermarkets?
A. To make them ripen more quickly.                B. To make them ripen more slowly.
C. To make banana flesh soften.                        D. To turn green bananas yellow.

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Wind is the movement of air from an area of high pressure to an area of low pressure. In fact, wind exists because the sun unequally heats the surface of the Earth. As hot air rises, cooler air moves in to fill the gap. As long as the sun shines, the wind will blow. And as long as the wind blows, people will manage it to power their lives.
Ancient sailors used sails to capture the wind and explore the world. Farmers once used windmills to grind their grains and pump water. Today, more and more people are using wind turbines to make electricity from the breeze. Over the past decade, wind turbine use has increased at more than 25 percent a year. Still, it only provides a small part of the world's energy.
Most wind energy comes from turbines that can be as tall as a 20-story building and have three 200-foot-long (60-meter-long) blades. These devices look like giant airplane propellers(螺桨)on a stick. The wind spins the blades, which turn a shaft connected to a generator.
The biggest wind turbines generate enough electricity to supply about 600 U.S. homes. Wind farms have tens and sometimes hundreds of these turbines lined up together in particularly windy spots, like along a ridge. Smaller turbines set up in a backyard can produce enough electricity for a single home or small business.
Wind is a clean source of renewable energy that produces no air or water pollution. And since the wind is free, operational costs are nearly zero once a turbine is erected. Mass production and technology advances are making turbines cheaper, and many governments decrease tax to encourage wind-energy development.
Some people think wind turbines are ugly and complain about the noise the machines make. The slowly rotating blades(螺旋风片) can also kill birds and bats, but not nearly as many as cars, power lines, and high-rise buildings do. The wind is also changeable: If it's not blowing, there's no electricity generated.
Nevertheless, the wind energy industry is increasing sharply. Globally, generation more than quadrupled(四倍) between 2000 and 2006. At the end of last year, global capacity was more than 70,000 megawatts. In the energy-hungry United States, a single megawatt is enough electricity to power about 250 homes. Germany has the most installed wind energy capacity, followed by Spain, the United States, India, and Denmark. Development is also fast growing in France and China.
Industry experts predict that if this pace of growth continues, by 2050 the answer to one third of the world's electricity needs will be found blowing in the wind
63. According to the passage, which of the following statements is true?
A. The rotating blades can kill as many birds as high-rise buildings do
B. Single families are not encouraged to build turbines.
C. The USA produces more wind power than any other country in the world.
D. The noise the turbines make may discourage people from building them.
64. The underlined word “generator” in the third paragraph probably means_______.
A. 电动机                       B. 发电机                          C. 机翼                               D. 飞机引擎
65. If the USA wants to build wind turbines in an area with 30,000 homes, how many
should they build at least?
A. 50.                                    B. 150.                                 C. 250.                                 D. 200.
66. All the following are the advantages of wind energy EXCEPT that_________.
A. it is environmentally friendly                                   B. it is free to build and operate
C. the government supports it                                              D. the energy is clean and renewable

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30. —This wall of air is an effective answer to the problem and it ______ work.
—But it is a question to put such a wall of air around the statue.

A.mayB.mustC.shouldD.Could

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Priscilla Ouchida’s “energy-efficient” house turned out to be a horrible dream. When she and her engineer husband married a few years ago, they built a $100,000 three-bedroom home in California. Tightly sealed to prevent air leaks, the house was equipped with small double-paned (双层玻璃的) windows and several other energy-saving features. Problems began as soon as the couple moved in, however. Priscilla’s eyes burned. Her throat was constantly dry. She suffered from headaches and could hardly sleep. It was as though she had suddenly developed a strange illness.

Experts finally traced the cause of her illness. The level of formaldehyde (甲醛) gas in her kitchen was twice the maximum allowed by federal standards for chemical workers. The source of the gas? Her new kitchen cabinets and wall-to-wall carpeting.

The Ouchidas are victims of indoor air pollution, which is net given sufficient attention partly because of the nation’s drive to save energy. The problem itself isn’t new. “The indoor environment was dirty long before energy conservation came along,” says Moschandreas a pollution scientist at Geomet Technologies in Maryland. “Energy conservation has tended to accentuate the situation in some cases.”

The problem appears to be more troublesome in newly constructed homes rather than old ones. Back in the days when energy was cheap, home builders didn’t worry much about unsealed cracks. Because of such leaks, the air in an average home was replaced by fresh outdoor air about once an hour. As a result, the pollutants produced in most households seldom build up to dangerous levels.

1. It can be learned from the passage that the Ouchidas’ house __________

A. is well worth the money spent on its construction

B. is almost faultless from the point of energy conservation

C. failed to meet energy conservation standards

D. was designed and constructed in a scientific way

2. What made the Ouchidas’ new house a horrible dream?

A. Lack of fresh air.                                  B. Poor quality of building materials.

C. Gas leak in the kitchen.                          D. The newly painted walls.

3. The underlined word “accentuate” in the third paragraph most probably means ___________.

A. control        B. worsen               C. relieve               D. improve

4. This passage is most probably taken from an article entitled “_________”.

A. Energy Conservation                             B. Houses Building Crisis

C. Air Pollution Indoors                             D. Traps in Building Construction

 

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