Passage One
There are more than 100 million cars in the United States. A normal car gets less than 15 miles from each gallon of gas. It travels about 10,000 miles each year. In that time, it uses about 650 gallons of gas. In all, autos use up some 70 billion gallons of gas a year. That comes out to be four-and-a-half million barrels a day.
The importance of saving gas, then, cannot be stressed too much. Let’s say, for instance, that the fuel used by each car could be cut back just 15 percent. This could be done by making fewer trips each day. It could be done through better driving habits. If it were done, our nation’s use of fuel would fall by close to two-thirds of a million barrels per day.
We can all help save gas. One way is to ride the buses. Some of us could walk to work. We could ride mopeds(机动脚踏两用车) or bikes. Another way is to share a ride. We could join carpools (合伙使用汽车). About one-third of all cars are used for going to and from work.
Go shopping with a friend from time to time. If two people use a car instead of one, we all save. There would be fewer cars on the road. The savings on gas around the nation would come to more than one half million barrels a day.
Another way to save is by cutting our useless trips. Can you find one car trip per week that could be handled by telephone Can you combine trips If each car took one less 10-mile trip a week, we could save three-and-half billion gallons of gas a year. This comes to nearly 5 percent of the total passenger car demand for gas.
The way people drive decides how much fuel they save. Careful drivers may get20 percent more miles per gallon than normal drivers. They could get 50 percent more miles per gallon than wasteful drivers. Careful drivers obey the 55-mile-per-hour speed limit. They get to their desired speed quickly and keep a steady pace.
If just one gallon of gas were saved each week for each car in the country, we could all save about five-and-half billion gallons a year.

What is the main idea of the passage（）

A:Americans need to save gas. B:Gas prices continue to rise. C:Small cars get good gas mileage. D:Automobiles cause serious air pollution.

Oil and gas will run out too fast for doomsday global warming scenarios to materialize, according to a controversial new analysis presented this week at the University of Uppsala in Sweden. The authors warn that all the fuel will be burnt before there is enough carbon dioxide in the atmosphere to realize predictions of melting ice caps and searing temperatures. Defending their predictions, scientists from the Intergovernmental Panel on Climate Change say they considered a range of estimates of oil and gas reserves, and point out that coal-burning could easily make up the shortfall. But all agree that burning coal would be even worse for the planet.
The IPCC’s predictions of global meltdown pushed forward the 1997 Kyoto Protocol, an agreement obliging signatory nations to cut CO₂ emissions. The IPCC considered a range of future scenarios, from unlimited burning of fossil-fuels to a fast transition towards greener energy sources. But geologists Anders Sivertsson, Kjell Aleklett and Colin Campbell of Uppsala University say there is not enough oil and gas left even the most conservative of the 40 IPCC scenarios to come to pass.
Although estimates of oil and gas reserves vary widely, the researchers are part of a growing group of experts who believe that oil supplies will peak as soon as 2010, and gas soon after. Their analysis suggests that oil and gas reserves combined about to the equivalent of about 3,500 billion barrels of oil considerably less than the 5,000 billion barrels estimated in the most optimistic model envisaged by the IPCC. Even the average forecast of about 8,000 billion barrels is more than twice the Swedish estimate of the world’s remaining reserves.
Nebojsa Nakicenovic, an energy economist at the University of Vienna, Austria who headed the 80-strong IPCC team that produced the forecasts, says the panel’s work still stands. He says they factored in a much broader and internationally accepted range of oil and gas estimates than the "conservative" Swedes.
Even if oil and gas run out, "there’s a huge amount of coal underground that could be exploited", he says that burning coal could make the IPCC scenarios come true, but points out that such a switch would be disastrous. Coal is dirtier than oil and gas and produces more CO₂ for each unit of energy, as well as releasing large amounts of particulates. He says the latest analysis is a "shot across the bows" for policy makers.

In the last paragraph, what does the word "switch" stand for（　）

A:Coal-burning to replace the oil and gas. B:Fossil fuels to replace the oil and gas. C:Green fuels to replace the oil and gas. D:The oil and gas to replace the coal-burning.

What comes to mind when you think of a lake You probably imagine a pretty scene with blue water, birds, and fish. For the people in the northwestern Cameroon, however, the image is very different. For them, lakes may mean terrible disasters. In 1984, poisonous gases exploded out of Lake Monoun and came down into the nearby villages, killing thirty-seven people. Two years later, Lake Nyos erupted. A cloud of gases rolled down the hills and into the valleys and killed 1,700 people.
Lake Nyos and Lake Monoun are crater (火山口) lakes. They were formed when water collected in the craters of old volcanoes. The volcanoes under Lake Nyos and Lake Monoun are not active anymore. However, poisonous gases from the center of the earth continue to flow up through cracks in the bottom of the lake. This is normal in a crater lake. In most crater lakes, these gases are released often because the water "turns over" regularly. That is, the water from the bottom of the lake rises and mixes with the water at the top, allowing the gases to escape slowly.
However, in Lakes Nyos and Monoun, there is no regular turning over. No one knows the reason for this fact, but as a result, these lakes have more gases trapped at the bottom than other crater lakes. In fact, scientists who have studied Lakes Nyos and Monoun have found 16,000 times more gases. When a strong wind, cool weather, a storm, or a landslide (划破) causes the water to turn over suddenly, the gases escape in a violent explosion.
In the past, no one knew when the gases might explode, so there was no way for the villagers to escape disaster. Now scientists from the United States, France, and Cameroon have found a way to reduce the gas pressure at the bottom of Lake Nyos. They stood a 672-foot plastic pipe in the middle of the lake, with one end of the pipe near the bottom and the other end in the air. Near the top of the pipe, the team put several holes that could be opened or closed by a computer. Now, when the gas pressure gets too high, the holes are opened and some of the gas-filled water shoots up through the pipe into the air like a fountain. With less pressure, a disastrous explosion is much less likely. However, the scientists are not sure that one pipe will be enough to prevent explosions. They hope to put in others soon and they plan to install a similar pipe and a computer system at Lake Monoun as well.
To protect people nearby until all of the pipes are in place, the scientists have installed early warning systems at both lakes. If the gas pressure rises to a dangerous level, computers will set off loud sirens (警报) and bright lights to warn the people in the villages. That way, they will have time to escape from the dangerous gases.
What do we learn from the last paragraph

A:Scientists are planning to install pipes in all crater lakes. B:Scientists still do not know how to prevent gas explosions. C:Explosion disasters could be avoided in the future. D:Warning systems have been set up in the villages nearby.

What comes to mind when you think of a lake You probably imagine a pretty scene with blue water, birds, and fish. For the people in the northwestern Cameroon, however, the image is very different. For them, lakes may mean terrible disasters. In 1984, poisonous gases exploded out of Lake Monoun and came down into the nearby villages, killing thirty-seven people. Two years later, Lake Nyos erupted a cloud of gases rolled down the hills and into the valleys and killed 1,700 people.
Lake Nyos and Lake Monoun are crater (火山口) lakes. They were formed when water collected in the craters of old volcanoes. The volcanoes under Lake Nyos and Lake Monoun are not active anymore. However, poisonous gases from the center of the earth continue to flow up through cracks in the bottom of the lake. This is normal in a crater lake. In most crater lakes, these gases are released often because the water "turns over" regularly. That is, the water from the bottom of the lake rises and mixes with the water at the top, allowing the gases to escape slowly.
However, in Lakes Nyos and Monoun, there is no regular turning over. No one knows the reason for this fact, but as a result, these lakes have more gases tapped at the bottom than other crater lakes. In fact, scientists who have studied Lakes Nyos and Monoun have found 16,000 times more gases. When a strong wind, cool weather a storm, or a landslide causes the water to turn over suddenly, the gases escape in a violent explosion.
In the past, no one knew when the gases might explode, so there was no way for the villagers to escape disaster. Now scientists from the United States, France, and Cameroon have found a way to reduce the gas pressure at the bottom of Lake Nyos. They stood a 672-foot plastic pipe in the middle of the lake, with one end of the pipe near the bottom and the other end in the air. Near the top of the pipe, the team put several holes that could be opened or closed by a computer. Now, when the gas pressure gets too high, the holes are opened and some of the gas-filled water shoots up through the pipe into the air like a fountain. With less pressure, a disastrous explosion is much less likely. However, the scientists are not sure that one pipe will be enough to prevent explosions. They hope to put in others soon and they plan to install a similar pipe and a computer system at Lake Monoun as well.
To protect people nearby until all of the pipes are in place, the scientists have installed early warning systems at both lakes. If the gas pressure rises to a dangerous level, computers will set off loud sirens (警报) and bright lights to warn the people in the villages. That way, they will have time to escape from the dangerous gases.
What do we learn from the last paragraph

A:Scientists are planning to install pipes in all crater lakes. B:Scientists still do not know how to prevent gas explosions. C:Explosion disasters could be avoided in the future. D:Warning systems have been set up in the villages nearby.

{{B}}第三篇{{/B}}

In the last paragraph, what does the word "switch" stand for?

A:Coal-burning to replace the oil and gas. B:Fossil fuels to replace the oil and gas. C:Green fuels to replace the oil and gas. D:The oil and gas to replace the, coal-burning.

{{B}}第三篇{{/B}}

What do we learn from the last paragraph?

A:Scientists are planning to install pipes in all crater lakes. B:Scientists still do not know how to prevent gas explosions. C:Explosion disasters could be avoided in the future. D:Warning systems have been set up in the villages nearby.

第三篇 The Exploding Lakes of Cameroon What comes to mind when you think of a lake? You probably imagine a pretty scene with blue water，birds，and fish．For the people in the northwestern Cameroon，however, the image is very different. For them，lakes may mean terrible disasters. In 1984，poisonous gases exploded out of Lake Monoun and came down into the nearby villages，killing thirty—seven people．Two years later,Lake Nyos erupted A cloud of gases rolled down the hills and into the valleys and killed 1,700 people． Lake Nyos and Lake Monoun are crater(火山口)lakes They were formed when water collected in the craters of old volcanoes The volcanoes under Lake Nyos and Lake Monoun are not active anymore. However, poisonous gases from the center of the earth continue to flow up through cracks in the bottom of the lake. This is normal in a crater lake. In most crater lakes，these gases are released often because the water‘turns over’regularly．That is，the water from the bottom of the lake rises and mixes with the water at the top，allowing the gases to escape slowly． However，in Lakes Nyos and Monoun，there is no regular turning over．No one knows the reason for this fact，but as a result，these lakes have more gases tapped at the bottom than other crater lakes. In fact，scientists who have studied Lakes Nyos and Monoun have found 16,000 times more gases．When a strong wind，cool weather a storm，or a landslide(滑坡)causes the water to turn over suddenly，the gases escape in a violent explosion． In the past，no one knew when the gases might explode，so there was no way for the villagers to escape disaster. Now scientists from the United States，France，and Cameroon have found a way to reduce the gas pressure at the bottom of Lake Nyos．They stood a 672-foot plastic pipe in the middle of the lake，with one end of the pipe near the bottom and the other end in the air．Near the top of the pipe，the team put several holes that could be opened or closed by a computer．Now，when the gas pressure gets too high，the holes are opened and some of the gas-filled water shoots up through the pipe into the air like a fountain．With less pressure，a disastrous explosion is much less likely．However, the scientists are not sure that one pipe will be enough to prevent explosions．They hope to put in others soon and they plan to install a similar pipe and a computer system at Lake Monoun as well． To protect people nearby until all of the pipes are in place．the scientists have installed early warning systems at both lakes. If the gas pressure rises to a dangerous level，computers will set off loud sirens(警报)and bright lights to warn the people in the villages．That way, they will have time to escape from the dangerous gases． What do we learn from the last paragraph?

A:Scientists are planning to install pipes in all crater lakes． B:Scientists still do not know how to prevent gas explosions C:Explosion disasters could be avoided in the future D:Warning systems have been set up in the villages nearby．

Central heating became popular only after the Civil War. Typically, coal-burning furnaces (火炉) fueled the early systems. Natural gas had developed into the leading fuel by 1960. Its acceptance resulted in part from its wide uses. Because it comes primarily from U.S. and Canadian fields, natural gas is also less vulnerable (脆弱的) than oil is to War. Oil remains the most important fuel in a few areas, such as New England.
Electric heating dominates most areas with mild winters and cheap electricity, including the South and the Northwest. It was made popular at least in the South by the low cost of adding electric heating to new houses built with air-conditioning. Bottled gas, which is somewhat more expensive than utility gas, is the fuel of choice in rural areas not served by utility pipelines. Wood is the leading heating fuel in just a few rural counties.
Home heating, which accounts for less than 7 percent of all energy consumed in the U.S., has had a commendable (值得赞扬的) efficiency record: from 1978 to 1997, the amount of fuel consumed for this purpose declined 44 percent despite a 33 percent increase in the number of housing units and an increase in house size. The U.S. Department of Energy, however, forecasts that energy used in home heating will rise by 14 percent over the next two decades. That rise is small considering an expected 21 percent increase in the number of houses and the trend toward larger houses.
Natural gas and electricity will probably dominate the home heating market for the next two decades. Solar (太阳的) heating never became popular because of cost and limited winter sunlight in most areas; in 2000 only 47,000 homes relied on it.
What fuel is the dominant fuel in New England

A:Gas. B:Electricity. C:Wood. D:Oil.

Home Heating
Central heating became popular only after the Civil War. Typically, coal-burning furnaces (火炉) fueled the early systems. Natural gas had developed into the leading fuel by 1960. Its acceptance resulted in part from its wide uses. Because it comes primarily from U.S. and Canadian fields, natural gas is also less vulnerable (脆弱的) than oil is to war. Oil remains the most important fuel in a few areas, such as New England.
Electric heating dominates most areas with mild winters and cheap electricity, including the South and the Northwest. It was made popular at least in the South by the Iow cost of adding electric heating to new houses built with air-conditioning. Bottled gas, which is somewhat more expensive than utility gas, is the fuel of choice in rural areas not served by utility pipelines. Wood is the leading heating fuel in just a few rural counties.
Home heating, which accounts for less than 7 percent of all energy consumed in the U.S., has had a commendable (值得赞扬的) efficiency record: from 1978 to 1997, the amount of fuel consumed for this purpose declined 44 percent despite a 33 percent increase in the number of housing units and an increase in house size. The U. S. Department of Energy, however, forecasts that energy used in home heating will rise by 14 percent over the next two decades. That rise is small considering an expected 21 percent increase in the number of houses and the trend toward larger houses.
Natural gas and electricity will probably dominate the home heating market for the next two decades. Solar (太阳的) heating never became popular because of cost and limited winter sunlight in most areas; in 2000 only 47, 000 homes relied on it.
What fuel is the dominant fuel in New England

A:Gas. B:Electricity. C:Wood. D:Oil.