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A single 10-second kiss can transfer as many as 80 million bacteria, according to Dutch scientists.
They monitored the kissing behavior of 21 couples and found those who kissed nine times a day were most likely to share salivary bugs (唾液细菌).
Studies suggest the mouth is home to more than 700 different types of bacteria – but the report reveals some are exchanged more easily than others.
The research is published in the journal Microbiome (微生物组). A team from the Netherlands Organization for Applied Scientific Research (TNO) asked the couples a series of quest
ions to assess their kissing habits, including how frequently they had kissed in the last year and when they last locked lips.
Scientists took bacterial samples from the volunteers tongues and saliva before and after a strictly timed 10-second kiss. One member of the couples then drank a probiotic (益生菌) drink, containing an easily identifiable mixture of bugs. On the couple’s second kiss, scientists were able to detect the volume of bacteria transferred to the other partner – on average 80 million bacteria in a single 10-second kiss. But while bacteria in the saliva seemed to change quickly in response to a kiss, bug populations on the tongue remained more stable.
Prof Remco Kort, who led the research, said: “French kissing is a great example of exposure to a gigantic（巨大的）number of bacteria in a short time.
These types of investigations may help us design future bacterial therapies and help people with troublesome bacterial problems.
A growing number or researchers are looking at the microbiome an ecosystem of some 100 trillion micro-organisms that live in and on our bodies. Scientists say these populations may be essential for health and the prevention of disease.
1.According to the passage, bacteia can be exchanged during a kiss through .
A. saliva B. tongues C. lips D. breath
2.Why did the scientists have one of the couples drink a probiotic drink?
A. Because they want to observe the response of their bodies.
B. Because they intend to protect the bacteria in the couples’ mouths,
C. Because they want to detect the volume of the transferred bacteria.
D. Because they want to keep a balanced environment in the couples’ bodies.
3.What’s the purpose of the research?
A. To guide healthy kiss.
B. To limit the times of kissing.
C. To avoid kissing different people.
D. To help design future bacteria therapies.
4.We can learn from the passage that .
A. French kissing should be advocated
B. we need to lock lips when kissing if we love her / him
C. the exchanged bacteria through kissing do great harm to the other
D. some of the microbiome may be essential for health though exchanged during a kiss
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There might be as many as 10 million species of complex life on this planet today —— a huge number. But add up all of the complex species that ever lived and some biologists think the grand total would be about five billion. The estimate leads to an astonishing conclusion: a staggering 99% of species are not around any more. They have been driven to extinction.
More species are joining the ranks of the extinct every year. Many scientists believe we are living through an episode of remarkably rapid extinction, on a scale that has been seen only five times in the last half a billion years.
They call this current episode the sixth mass extinction —— a large, global decline in a wide variety of species over a relatively short period of time. And they tend to agree that humans are the main cause.
Over-hunting, overfishing, and human-driven habitat loss are pushing many species to the brink. In fact, we have changed the planet so much that some geologists are now suggesting that we have entered a new phase in Earth’s history; an epoch they call the ＂Anthropocene＂. By 2100, it is expected that humans will have caused the extinction of up to half of the world’s current species.
Because we are living through this extinction, it is relatively easy for us to study the driving forces behind it. But how do we determine what caused other mass die-offs that happened long ago? To do so we have to look at what archaeologists, palaeontologists, geologists and other scientists have concluded from the evidence they have gathered.
The trouble is, those scientists do not always agree with one another —— even about the most recent extinction event. As well as the five-or six- mass extinctions, there have also been many smaller extinctions.
One of these mini extinction events happened towards the end of the Pleistocene, a few tens of thousands of years ago. It is sometimes called the ＂megafaunal＂ extinction because many of the species it claimed were particularly large animals, weighing more than 97lb (44kg). However, its cause remains a debate amongst scientists.
1.What can we learn about the sixth mass extinction？
A. Humans are the main cause of it.
B. It means a global decline over a long time.
C. It occurred towards the end of the Pleistocene.
D. Scientists still disagree about the cause of it.
2.What can be inferred from the text about species？
A. 99% of species will not be around any more by 2100.
B. By the 22nd century, there will probably be about five million on this planet.
C. About eight years later we will enter what is called the ＂Anthropocene＂.
D. It is not easy for us to figure out causes behind the＂Anthropocene＂.
3.Which of the following is closest in meaning to the underlined word in the last paragraph ?
A. Land animals. B. Marine life.
C. Huge animals. D. Flesh-eating creatures.
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Solar energy for your home is coming. It can help you as a single home owner. It can help the whole country as well. Whether or not solar energy can save your money depends on many things. Where you live is one factor. The type of home you have is another. Things like insulation(绝缘) present energy costs and the type of system you buy are added factors.
Using solar energy can help save our precious fuel. As you know, our supplies of oil and gas are very limited. There is just not enough on hand to meet all our future energy needs. And when Mother Nature says that’s all, the only way we can delay hearing those words is by starting to save energy now and by using other sources, like the sun.
We won’t have to worry about the sun’s running out of energy for another several billion years or so. Besides begin an endless source of energy, the use of the sun has other advantages as well. The sun doesn’t offer as many problems as other energy sources. For example, fossil fuel plants add to already high pollution levels. With sola energy, we will still need sources of energy, but we won’t need as much. That means we can cut down on our pollution problems.
With all these good points, why don’t we use more solar power? There are many reasons for this. The biggest reason is money. Until now, it was just not practical for a home owner to put in a solar unit. There were cheaper sources of energy. All this is changing now. Solar costs are starting to equal the costs of oil and electricity. Experts say that gas, oil and electricity prices will continue to rise. The demand for electricity is increasing rapidly. But new power plants will use more gas, oil or coal. Already in some places the supply of electricity is being rationed. Solar energy is now in its infancy. It could soon grow to become a major part of our nation’s energy supply.
57. Which statement best expresses the main idea?
A. Something about Solar Energy and Pollution. B. Solar Energy.
C. Energy and Pollution D. Energy and Money
58. Solar energy can help us save ____.
A. the earth and nature resources B. mother nature
C. the sun D. our precious fuel
59. Which of the following statements is correct?
A. Energy from coal would not pollute our living environment.
B. Energy from natural gas would not pollute our living environment.
C. Energy from the sun would not pollute our living environment.
D. Energy from oil would not pollute our living environment.
60. Solar energy is in its infancy, ____.
A. but it will be considered as an important part of our nation’s energy supply
B. yet we will build more power plants
C. and the supply of electricity will be rationed
D. but we don’t need practice energy rationing now
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Malaria, the world's most widespread parasitic (寄生虫引起的)disease, kills as many as three million people every year ---- almost all of whom are under five, very poor, and African. In most years, more than five hundred million cases of illness result from the disease, although exact numbers are difficult to assess because many people don't (or can't) seek care. It is not unusual for a family earning less than two hundred dollars a year to spend a quarter of its income on malaria treatment, and what they often get no longer works. In countries like Tanzania, Mozambique, and the Gambia, no family, village, hospital, or workplace can remain unaffected for long.
Malaria starts suddenly, with violent chills, which are soon followed by an intense fever and, often, headaches. As the parasites multiply, they take over the entire body. Malaria parasites live by eating the red blood cells they infect (感染) .They can also attach themselves to blood vessels in the brain. If it doesn't kill you, malaria can happen again and again for years. The disease is passed on to humans by female mosquitoes infected with one of four species of a parasite. Together, the mosquito and the parasite are the most deadly couple in the history of the earth and one of the most successful. Malaria has five thousand genes, and its ability to change rapidly to defend itself and resist new drugs has made it nearly impossible to control. Studies show that mosquitoes are passing on the virus more frequently, and there are more outbreaks in cities with large populations. Some of the disease's spread is due to global warming.
For decades, the first-choice treatment for malaria parasites in Africa has been chloroquine, a chemical which is very cheap and easy to make. Unfortunately, in most parts of the world, malaria parasites have become resistant to it. Successful alternatives that help prevent resistance are already available, but they have been in short supply and are very expensive. If these drugs should fail, nobody knows what would come next.
1. According to paragraph 1, many people don't seek care because ___________.
A. they are too poor
B. it is unusual to seek care
C. they can remain unaffected for long
D. there are too many people suffering from the disease
2. People suffering from malaria _____________.
A. have to kill female mosquitoes B. have ability to defend parasites
C. have their red blood cells infected D. have sudden fever, followed by chills
3. Which of the following may be the reason for the wide spread of the disease?
A. Its resistance to global warming.
B. Its ability to pass on the virus frequently.
C. Its outbreaks in cities with large populations.
D. Its ability to defend itself and resist new drugs.
4. It can be inferred from the passage that _____________.
A. no drugs have been found to treat the disease
B. the alternative treatment is not easily available to most people
C. malaria has developed its ability to resist parasites
D. nobody knows what will be the drug to treat the disease
5. Which of the following questions has NOT been discussed in the passage?
A. How can we know one is suffering from malaria?
B. How many people are killed by malaria each year?
C. Why are there so many people suffering from malaria?
D. What has been done to keep people unaffected for long?
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Malaria, the world's most widespread parasitic(寄生虫引起的) disease, kills as many as three million people every year—almost all of whom are under five, very poor, and African. In most years, more than five hundred million cases of illness result from the disease, although exact numbers are difficult to assess because many people don't (or can't) seek care. It is not unusual for a family earning less than two hundred dollars a year to spend a quarter of its income on malaria treatment, and what they often get no longer works. In countries like Tanzania, Mozambique, and the Gambia, no family, village, hospital, or workplace can remain unaffected for long.
Malaria starts suddenly, with violent chills, which are soon followed by an intense fever and, often, headaches. As the parasites multiply, they take over the entire body. Malaria parasites live by eating the red blood cells they infect (感染). They can also attach themselves to blood vessels in the brain. If it doesn't kill you, malaria can happen again and again for years. The disease passed on to humans by female mosquitoes infected with one of four species of parasite. Together, the mosquito and the parasite are the most deadly couple in the history of the earth—and one of the most successful. Malaria has five thousand genes, and its ability to change rapidly to defend itself and resist new drugs has made it nearly impossible to control. Studies show that mosquitoes are passing on the virus more frequently, and there are more outbreaks in cities with large populations. Some of the disease's spread is due to global warming.
For decades, the first-choice treatment for malaria parasites in Africa has been chloroquine, a chemical which is very cheap and easy to make. Unfortunately, in most parts of the world, malaria parasites have become resistant to it. Successful alternatives that help prevent resistance are already available, but they have been in short supply and are very expensive. If these drugs should fail, nobody knows what would come next.
1.According to paragraph 1, many people don't seek care because___.
A. they are too poor
B. it is unusual to seek care
C. they can remain unaffected for long
D. there are too many people suffering from the disease
2.People suffering from malaria___.
A. have to kill female mosquitoes
B. have ability to defend parasites
C. have their red blood cells infected
D. have sudden fever, followed by chills
3.Which of the following may be the reason for the wide spread of the disease?
A. Its resistance to global warming.
B. Its ability to pass on the virus frequently.
C. Its outbreaks in cities with large populations.
D. Its ability to defend itself and resist new drugs.
4.It can be inferred from the passage that___.
A. no drugs have been found to treat the disease
B. the alternative treatment is not easily available to most people
C. malaria has developed its ability to resist parasites
D. nobody knows what will be the drug to treat the disease
5.Which of the following questions has NOT been discussed in the passage?
A. How can we know one is suffering from malaria?
B. How many people are killed by malaria each year?
C. Why are there so many people suffering from malaria7
D. What has been done to keep people unaffected for long7
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Malaria, the world's most widespread parasitic(寄生虫引起的) disease, kills as many as three million people every year—almost all of whom are under five, very poor, and African. In most years, more than five hundred million cases of illness result from the disease, although exact numbers are difficult to assess because many people don't (or can't) seek care. It is not unusual for a family earning less than two hundred dollars a year to spend a quarter of its income on malaria treatment, and what they often get no longer works. In countries like Tanzania, Mozambique, and the Gambia, no family, village, hospital, or workplace can remain unaffected for long.
Malaria starts suddenly, with violent chills, which are soon followed by an intense fever and, often, headaches. As the parasites multiply, they take over the entire body. Malaria parasites live by eating the red blood cells they infect (感染). They can also attach themselves to blood vessels in the brain. If it doesn't kill you, malaria can happen again and again for years. The disease passed on to humans by female mosquitoes infected with one of four species of parasite. Together, the mosquito and the parasite are the most deadly couple in the history of the earth—and one of the most successful. Malaria has five thousand genes, and its ability to change rapidly to defend itself and resist new drugs has made it nearly impossible to control. Studies show that mosquitoes are passing on the virus more frequently, and there are more outbreaks in cities with large populations. Some of the disease's spread is due to global warming.
For decades, the first-choice treatment for malaria parasites in Africa has been chloroquine, a chemical which is very cheap and easy to make. Unfortunately, in most parts of the world, malaria parasites have become resistant to it. Successful alternatives that help prevent resistance are already available, but they have been in short supply and are very expensive. If these drugs should fail, nobody knows what would come next.
1. According to paragraph 1, many people don't seek care because___.
A. they are too poor
B. it is unusual to seek care
C. they can remain unaffected for long
D. there are too many people suffering from the disease
2.People suffering from malaria___.
A. have to kill female mosquitoes
B. have ability to defend parasites
C. have their red blood cells infected
D. have sudden fever, followed by chills
3.Which of the following may be the reason for the wide spread of the disease?
A. Its resistance to global warming.
B. Its ability to pass on the virus frequently.
C. Its outbreaks in cities with large populations.
D. Its ability to defend itself and resist new drugs.
4.It can be inferred from the passage that___.
A. no drugs have been found to treat the disease
B. the alternative treatment is not easily available to most people
C. malaria has developed its ability to resist parasites
D. nobody knows what will be the drug to treat the disease
5.Which of the following questions has NOT been discussed in the passage?
A. How can we know one is suffering from malaria?
B. How many people are killed by malaria each year?
C. Why are there so many people suffering from malaria7
D. What has been done to keep people unaffected for long7
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As a single mother of three children, she has very little time ________ she can spare to develop her own interest.
A．when B．that
C．which D．what
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Steps to Retire as a Millionaire
Having a million-dollar savings is a retirement dream for many people. Making that dream come true requires some serious efforts. While success is never a sure thing, the steps outlined below will go a long way toward helping you achieve your objective.
1.
Vacations, cars, kids and all of life’s other expenses take a big chunk(大块) out of your paycheck. To maximize your savings, you need to minimize your expenses. Buying a home you can afford and living a lifestyle that is below your means and not funded by credit cards are all necessities if you want to boost your savings.
2.
If you don’t save, you’ll never reach your goal. Obvious as this might seem, far too many people never even start to save. If your employer offers a 401(k) plan (一种养老保险), simply sign up for the plan and contributions will be automatically taken out of your paycheck, increasing your savings and decreasing your taxes. It’s like getting a guaranteed return on your investment. Finding the cash to stash (隐藏起) may be a challenge, particularly when you’re young, but don’t let that stop you from pursuing future riches.
3.
If you are looking to grow your wealth over time, fixed income isn’t likely to get the job done, and inflation (通货膨胀) can take a big chunk out of your savings. Investing in equities (股票) may have more risk, but is also statistically likely to lead to greater returns. For many of us, it’s a risk we have to take if want to see our wealth grow.
4.
Part of long-term planning involves accepting the idea that setbacks will occur. If you are not prepared, these setbacks can put a stop to your savings efforts. While you can’t avoid all of the bumps in the road, you can prepare in advance to reduce the damage they can do.
5.
Your income should rise as time passes. You’ll get raises, you’ll change jobs, and maybe you’ll get married and become a two-income family. Every time more cash comes in to your pocket, you should increase the amount that you save. The key to reaching your goal as quickly as possible is to save as much as you can.
A. Watch Your Spending.
B. Prepare for Rainy Days.
C. Start Saving.
D. Get Aggressive.
E. Save More.
F. Set the Goal.
G. Have patience.
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Steps to Retire as a Millionaire
Having a million-dollar savings is a retirement dream for many people．Making that dream come true requires some serious efforts．While success is never a sure thing，the steps outlined below will go a long way toward helping you achieve your objective．
1.Vacations，cars，kids and all of life's other expenses take a big chunk(大块) out of your paycheck．To maximize your savings，you need to minimize your expenses．Buying a home you can afford and living a lifestyle that is below your means and not funded by credit cards are all necessities if you want to boost your savings．
2.If you don't save，you'll never reach your goal．Obvious as this might seem，far too many people never even start to save．If your employer offers a 401(k) plan (一种养老保险)，simply sign up for the plan and contributions will be automatically taken out of your paycheck，increasing your savings and decreasing your taxes．It's like getting a guaranteed return on your investment．Finding the cash to stash (隐藏起)may be a challenge，particularly when you're young，but don't let that stop you from pursuing future riches．
3.If you are looking to grow your wealth over time，fixed income isn't likely to get the job done，and inflation (通货膨胀) can take a big chunk out of your savings．Investing in equities (股票) may have more risk，but is also statistically likely to lead to greater returns．For many of us，it's a risk we have to take if want to see our wealth grow．
4.Part of long-term planning involves accepting the idea that setbacks will occur．If you are not prepared，these setbacks can put a stop to your savings efforts．While you can't avoid all of the bumps in the road，you can prepare in advance to reduce the damage they can do．
5.Your income should rise as time passes．You'll get raises，you'll change jobs，and maybe you'll get married and become a two-income family．Every time more cash comes in to your pocket，you should increase the amount that you save．The key to reaching your goal as quickly as possible is to save as much as you can．
A． Watch Your Spending．
B． Prepare for Rainy Days．
C． Start Saving．
D． Get Aggressive．
E． Save More．
F． Set the Goal．
G． Have patience．
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AIDS-related illnesses have killed more than 30 million people since 1981. That's half as many deaths as in World War II. And it's not over. An estimated 1.1 million Americans are among the 33 million people worldwide who are now living with HIV, the virus that causes AIDS.
Between 1884 and 1924, somewhere near modern-day Kinshasa in West Central Africa, a hunter kills a chimpanzee. Some of the animal's blood enters the hunter's body, possibly through an open wound. The blood carries a virus harmless to the chimp but deadly to humans: HIV.
In June, 1981, the CDC publishes a report from Los Angeles of five young homosexual men with fatal or life-threatening PCP pneumonia. First cases recognized. In 1985, Rock Hudson dies of AIDS. Larry Kramer's AIDS play, "The Normal Heart." shocks New York audiences.
In 1986, for the first time, President Reagan publicly utters the word "AIDS." In 1987, Princess Diana is photographed hugging people with AIDS. Reagan makes his first speech on AIDS. Liberace dies of AIDS. Three years later, Photographer Robert Mapplethorpe dies of AIDS.
In 1988, the first World AIDS DAY is held on Dec. 1. During 1991-1992, the red ribbon is introduced as a symbol of AIDS solidarity(团结一致). But AIDS becomes the leading cause of death in U.S. men aged 25-44 and ten years later, AIDS becomes the leading cause of death worldwide for people aged 15 to 59.
In 2008, for the first time, global AIDS deaths decline. UNAIDS calculates that the global spread of AIDS peaked in 1996 at 3.5 million new infections. Deaths peaked in 2004, at 2.2 million. Yet AIDS Day 2009 brings surprising figures: 2.7 million new HIV infections and 2 million AIDS deaths in the previous year.
Researchers have discovered more than a dozen antibodies that target the HIV virus. They hope that these discoveries will lead to a vaccine that offers long-term protection against AIDS. One antibody in particular, PGT 128, is considered among the most potent and promising—preventing about 70% of viruses from infecting cells in laboratory tests.
1.What is the second paragraph mainly about?
A. HIV: from monkeys to humans. B. A hunter's killing caused HIV.
C. HIV is harmless to the chimpanzee. D. HIV is deadly to humans.
2.How many famous people died of AIDS mentioned in the passage between 1985 and 1991?
A. 2. B. 3. C. 4. D. 5.
3.Which of the following statements is true according to the passage?
A. The red ribbon and the World AIDS Day are both the symbols of AIDS solidarity.
B. In 2008, AIDS caused most deaths since 1981 and the death began to go down.
C. In 1986, President Reagan used the word "AIDS" and made a speech on it.
D. During 2001-2002, AIDS is the leading cause of death in the world aged 15 to 59.
4.What attitude does the author have towards the treatment to AIDS in the future?
A. Pessimistic. B. Optimistic. C. Objective. D. Uncertain.
ions to assess their kissing habits, including how frequently they had kissed in the last year and when they last locked lips.