单选题

Text 3
Fire can be thought of as any combustion process intense enough to emit light. It may be a quietly burning flame or the :brilliant flash of an explosion.
A typical combustion process is the burning of gasoline in an automobile engine. The vaporized fuel is mixed with air, compressed in the engine’ s cylinder, and ignited by a spark. As the fuel flame up, the heat produced flows into the adjacent layer of unburned fuel and ignites it. In this way a zone of fire spreads throughout the fuel mixture is called a combustion wave.
The speed at which such a combustion wave travels through a fuel mixture is called the burning velocity of the mixture. The burning velocity of a gas such as methane quietly burning in air is only about one foot per second. By comparison, the burning velocity of more reactive combinations such as the rocket Fuels, hydrogen and fluorine, can be hundreds of feet per second.
If the fuel flows at the same speed as the combustion wave, the result is a stationary flame, like the one in your kitchen gas burner. In the kitchen burner a jet of gas mixed with airflows from the opening in the head of the burner. If the velocity of the fuel mixture flowing from the opening is greater than its burning velocity, the flame blows out.
In jet engines speeding through the air at 500 to 600 miles per hour, the engine’ s flame is sometimes blown out by the blast of air entering the combustion chamber at high speeds. Jet pilots call this condition "flameout".
Combustion can sometimes occur very slowly. A familiar example of Slow combustion is the drying of ordinary oil-based paint. In this chemical reaction, called oxidation, the oxygen in the air reacts with the drying ’oil in the paint to provide a tough film. The linseed oil molecules link together, forming an insoluble coating.
How can the chemical reaction involved in such a quiet process as the drying of paint also produce spectacular flames and explosions The main difference between the two is the temperature at which they occur.
At lower temperatures the reaction must take place over a long time. The heat which is slowly produced is dissipated to the surroundings and does not speed up the reaction. When the heat produced by the low-temperature reaction is retained instead of being dissipated, the system breaks into flame.
In a flame or explosion, the reactions are extremely fast. In many chemical processes, however, such a rapid oxidation process would be extremely destructive.

Which of the following could not be defined as combustion（）

A:A quietly burning flame. B:An explosion. C:A radiator giving off heat. D:The drying of oil-based paint.

When there is blood in the water, it is only natural that dorsal fins swirl around excitedly. Now that America’s housing market is ailing, predators have their sights on the country’s credit-card market. Analysts at Goldman Sachs reckon that credit-card losses could reach $ 99 billion if contagion spreads from subprime mortgages to other forms of consumer credit. Signs of strain are clearly visible. There are rises in both the charge-off and delinquency rates, which measure the share of balances that are uncollectable or more than 30 days late respectively. HSBC announced last month that it had taken a $1.4 billion charge in its American consumer-finance business, partly because of weakness among card borrowers.
It is too early to panic, though. Charge-offs and delinquencies are still low. According to Moody’s, a rating agency, the third-quarter delinquency rate of 3.89% was almost a full percentage point below the historical average. The deterioration in rates can be partly explained by technical factors. A change in America’s personal-bankruptcy laws in 2005 led to an abrupt fall in bankruptcy filings, which in turn account for a big chunk of credit-card losses ; the number of filings (and thus charge-off rates) would be rising again, whether or not overall conditions for borrowers were getting worse.
The industry also reports solid payment rates, which show how much of their debt consumers pay off each month. And confidence in credit-card asset-backed securities is pretty firm despite paralysis in other corners of structured finance. Dennis Moroney of Tower Group, a research firm, predicts that issuance volumes for 2007 will end up being 25% higher than last year.
Direct channels of infection between the subprime-mortgage crisis and the credit-card market certainly exist: consumers are likelier to load up on credit-card debt now that home- equity loans are drying up. But card issuers look at cash flow rather than asset values, so falling house prices do not necessarily trigger a change in borrowers’ creditworthiness. They may even work to issuers’ advantage. The incentives for consumers to keep paying the mortgage decrease if properties are worth less than the value of the loan; card debt rises higher up the list of repayment priorities as a result.
Card issuers are also able to respond much more swiftly and flexibly to stormier conditions than mortgage lenders are, by changing interest rates or altering credit limits. That should in theory reduce the risk of a rapid repricing of assets. "We are not going to wake up one day and totally revalue the loans," says Gary Perlin, Capital One’ s chief financial officer.
If a sudden subprime-style meltdown in the credit-card market is improbable, the risks of a sustained downturn are much more real. If lower house prices and a contraction in credit push America into recession, the industry will undoubtedly face a grimmer future. Keep watching for those dorsal fins.
In what way does the subprime mortgage influence credit card market

A:The fall of asset values affects the card borrowers’ creditworthiness. B:The decrease in the mortgage payment leads to the rises of the card debt. C:As the home-equity loans are drying up, consumers are more likely to load up on the card debt. D:The falling house prices make the card debt rise higher.

Text 4

When there is blood in the water, it is only natural that dorsal fins swirl around excitedly. Now that America’s housing market is ailing, predators have their sights on the country’s credit-card market. Analysts at Goldman Sachs reckon that credit-card losses could reach $ 99 billion if contagion spreads from subprime mortgages to other forms of consumer credit. Signs of strain are clearly visible. There are rises in both the charge-off and delinquency rates, which measure the share of balances that are uncollectable or more than 30 days late respectively. HSBC announced last month that it had taken a $1.4 billion charge in its American consumer-finance business, partly because of weakness among card borrowers.
It is too early to panic, though. Charge-offs and delinquencies are still low. According to Moody’s, a rating agency, the third-quarter delinquency rate of 3.89% was almost a full percentage point below the historical average. The deterioration in rates can be partly explained by technical factors. A change in America’s personal-bankruptcy laws in 2005 led to an abrupt fall in bankruptcy filings, which in turn account for a big chunk of credit-card losses ; the number of filings (and thus charge-off rates) would be rising again, whether or not overall conditions for borrowers were getting worse.
The industry also reports solid payment rates, which show how much of their debt consumers pay off each month. And confidence in credit-card asset-backed securities is pretty firm despite paralysis in other corners of structured finance. Dennis Moroney of Tower Group, a research firm, predicts that issuance volumes for 2007 will end up being 25% higher than last year.
Direct channels of infection between the subprime-mortgage crisis and the credit-card market certainly exist: consumers are likelier to load up on credit-card debt now that home- equity loans are drying up. But card issuers look at cash flow rather than asset values, so falling house prices do not necessarily trigger a change in borrowers’ creditworthiness. They may even work to issuers’ advantage. The incentives for consumers to keep paying the mortgage decrease if properties are worth less than the value of the loan; card debt rises higher up the list of repayment priorities as a result.
Card issuers are also able to respond much more swiftly and flexibly to stormier conditions than mortgage lenders are, by changing interest rates or altering credit limits. That should in theory reduce the risk of a rapid repricing of assets. "We are not going to wake up one day and totally revalue the loans," says Gary Perlin, Capital One’ s chief financial officer.
If a sudden subprime-style meltdown in the credit-card market is improbable, the risks of a sustained downturn are much more real. If lower house prices and a contraction in credit push America into recession, the industry will undoubtedly face a grimmer future. Keep watching for those dorsal fins.
In what way does the subprime mortgage influence credit card market

A:The fall of asset values affects the card borrowers’ creditworthiness. B:The decrease in the mortgage payment leads to the rises of the card debt. C:As the home-equity loans are drying up, consumers are more likely to load up on the card debt. D:The falling house prices make the card debt rise higher.

When there is blood in the water, it is only natural that dorsal fins swirl around excitedly. Now that America’s housing market is ailing, predators have their sights on the country’s credit-card market. Analysts at Goldman Sachs reckon that credit-card losses could reach $ 99 billion if contagion spreads from subprime mortgages to other forms of consumer credit. Signs of strain are clearly visible. There are rises in both the charge-off and delinquency rates, which measure the share of balances that are uncollectable or more than 30 days late respectively. HSBC announced last month that it had taken a $1.4 billion charge in its American consumer-finance business, partly because of weakness among card borrowers.
It is too early to panic, though. Charge-offs and delinquencies are still low. According to Moody’s, a rating agency, the third-quarter delinquency rate of 3.89% was almost a full percentage point below the historical average. The deterioration in rates can be partly explained by technical factors. A change in America’s personal-bankruptcy laws in 2005 led to an abrupt fall in bankruptcy filings, which in turn account for a big chunk of credit-card losses ; the number of filings (and thus charge-off rates) would be rising again, whether or not overall conditions for borrowers were getting worse.
The industry also reports solid payment rates, which show how much of their debt consumers pay off each month. And confidence in credit-card asset-backed securities is pretty firm despite paralysis in other corners of structured finance. Dennis Moroney of Tower Group, a research firm, predicts that issuance volumes for 2007 will end up being 25% higher than last year.
Direct channels of infection between the subprime-mortgage crisis and the credit-card market certainly exist: consumers are likelier to load up on credit-card debt now that home- equity loans are drying up. But card issuers look at cash flow rather than asset values, so falling house prices do not necessarily trigger a change in borrowers’ creditworthiness. They may even work to issuers’ advantage. The incentives for consumers to keep paying the mortgage decrease if properties are worth less than the value of the loan; card debt rises higher up the list of repayment priorities as a result.
Card issuers are also able to respond much more swiftly and flexibly to stormier conditions than mortgage lenders are, by changing interest rates or altering credit limits. That should in theory reduce the risk of a rapid repricing of assets. "We are not going to wake up one day and totally revalue the loans," says Gary Perlin, Capital One’ s chief financial officer.
If a sudden subprime-style meltdown in the credit-card market is improbable, the risks of a sustained downturn are much more real. If lower house prices and a contraction in credit push America into recession, the industry will undoubtedly face a grimmer future. Keep watching for those dorsal fins.

In what way does the subprime mortgage influence credit card market（）

A:The fall of asset values affects the card borrowers’ creditworthiness B:The decrease in the mortgage payment leads to the rises of the card debt C:As the home-equity loans are drying up, consumers are more likely to load up on the card debt D:The falling house prices make the card debt rise higher

This kind of animals is on the verge of dying out.

A:drying up B:extinction C:dying off D:distinction

This kind of animals are on the verge of {{U}}extinction{{/U}}, because so many are being killed for their fur.

A:drying up B:dying out C:being exported D:being transplanted

This kind of animals are on the verge of extinction, because so many are being killed for their fur.

A:drying up B:dying out C:being transplanted D:being exported


? ?下面有3篇短文，每篇短文后有5道题，每道题后面有4个选项。请仔细阅读短文并根据短文回答其后面的问题，从4个选项中选择1个最佳答案填在题前的括号内。
{{B}}第一篇{{/B}}

? ? ? ? ? ? ? ? ?{{B}}A Thirsty World{{/B}}
? ?The world is not only hungry; it is also thirsty for water. This seems strange to you, since nearly 75% of the earth’s surface is covered with water. But about 97% of this huge amount is from sea-water, or salt water. Man can only drink and use the other 3%—the fresh water that comes from rivers, lakes, underground, and other sources. And we cannot even use all of that, because some of it is in the form of iceberg (冰山) and glaciers (冰川). Even worse, some of it has been polluted.
? ?At the moment, this small amount of fresh water is still enough for us. However, our need for water is increasing rapidly. Only if we take steps to deal with this problem now can we avoid a severe worldwide water shortage later on. A limited water supply would have a bad effect on agriculture and industry.
? ?In addition to stopping wasting our precious water, one useful step we should take is to develop ways of reusing it. Experiments have already been done in this field, but only on a small scale.
? ?Today, in most large cities tanks, water is used only once and it eventually returns to the sea or
runs into underground storage tanks. But it is possible to pipe water that has been used to a purifying (净化) plant. There it can be filtered (过滤) and treated with chemicals so that it can be used again just as it were fresh from a spring.
? ?But even if every large city purified and reused its water, we still would not have enough. Where could we turn next? To the oceans! All we’d have to do to make use of the vast amount of sea-water is—remove the salt. This salt-removing process is already in use in many parts of the world.
According to the passage, sea-water can be turned into fresh water by

A:heating it up B:treating it with chemicals C:taking salt out of it D:drying it up

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