WASHINGTON—Two-thirds of the world’s polar bear population could be gone by 2050 if predictions of melting sea ice hold true, the US Geological Survey reported on Friday.
The fate of polar bears could be even worse than that estimate, because sea ice in the Arctic might be disappearing faster than the available computer models predict, the geological survey said in a report aimed at determining whether the big white bear should be listed as a threatened species.
“There is a definite link between changes in the sea ice and the welfare of polar bears,” said Steve Amstrup, who led the research team. He says Arctic sea ice is already at the lowest this year and is expected to retreat(退却) farther this month.
That means that polar bears—some 16,000 of them -- will disappear by 2050 from parts of the Arctic where sea ice is melting most rapidly, along the north coasts of Alaska and Russia, researchers said in a telephone briefing(简报).
Other polar bears could survive beyond that date but many of those could be gone by 2100, Amstrup said. By this century’s end, the only polar bears left might live in the Canadian Arctic islands and along the west coast of Greenland.
“It is likely to result in loss of approximately two-thirds of the world’s current polar bear population by the mid 21st century,” the report’s executive summary said.
“Because the observed trajectory(轨迹)of Arctic sea ice decline appears to be underestimated by currently available models, this assessment of future polar bear status may be conservative(保守的).”
In January, the US Fish and Wildlife Service proposed listing the polar bear as a threatened species, noting polar bears depend on sea ice as a platform to hunt seals, their main food.
Without enough sea ice, polar bears would be forced onto land, but they are poor hunters once they get out of the water and ice, the researchers said. The bears’ disappearance would probably take place as young cubs(幼兽)failed to survive to adulthood and females were unable to reproduce successfully.What was the US Geological Survey intended to do?
| A．To determine whether the polar bear was in danger. |
| B．To measure how fast the sea ice melts in the Arctic. |
| C．To check the predictions of the computer models. |
| D．To find out the exact number of the polar bear. |
What causes the polar bears to disappear by 2050?
| A．The pollution of the Arctic region. | B．The sea ice melting at high speed |
| C．Fewer food sources being left. | D．The temperature getting colder. |
The key to preventing polar bears dying out seems to _______________.
| A．help young polar bears to survive the cold winter |
| B．have large number of seals living in the oceans |
| C．make sure there is enough sea ice in the Arctic |
| D．provide chances for adult polar bears to reproduce |
As people in Beijing and northern China struggle with severe air pollution this winter,the toxic(有毒的)air is also making life hard for plants and even food crops of China．
"in the last 50 years there has been a 1 6-fold increase in ozone(臭氧)pollution”in the Beijing area，said Hanqin Tian of Auburn University in Alabama,who studies the effects of China's pollution and climate change on plants．
Ozone is particularly harmful to plants because it damages the pores(气孔) on leaves，called stomata,which plants use to regulate how much water evaporates from the leaves．That，in turn，affectS how much water a plant must take up through its roots．Changes in water uptake by plants have been documented in other parts of the world，including the United States，as having major impacts on regional groundwater and surface water supplies．
In studies of the long-term productivity of plants，Hanqin Tian and some of his colleagues show that ozone pollution,along with climate change，has been lowering plant productivity in China,which reduces the amount of carbon and other pollutants that the plants Can absorb to fight all the emissions from the burning offossil fuels．
The worst effects on plants are likely to be in areas where the growing pollution problem is just fairly new, said Arthur Chappelka, also a plant researcher at Auburn University．Some plants are more resistant to pollutants than others，he said，and the plants that are living today in long-polluted urban areas are likely to be only those that are very pollution tolerant．
Away from the cities, however, where crops are necded to feed China’s yast population, the effeets of the growing pollution on crops is a significant concern.
“In some ways it affects the crop production and food securiy of China,”said Hanqin Tian.“Air quality is really important for human health, plants and ecosystem and sustainability.”
The problem is bound to get worse as China continues to develop economically, he said, and so he and other researchers continue to urge the Chinese government to take action to reduce emissions from cars and industries.ozone does harm to plants mainly by ________.
| A．exposing them to strong sunlight |
| B．damaging the structure of their leaves |
| C．adding more pores to the roots |
| D．making the land unfit for the plants to grow |
Which of the following statement does Hanqin Tian support?
| A．Ozone pollution has increased 1 6 times in the past 30 years． |
| B．Ozone pollution has lowered plant productivity alone． |
| C．Plants can take in a large amount of carbon and other pollutants． |
| D．The toxic air has few effects on food supply in China． |
What Can we infer from the passage?
| A．Healthy foods are not available in Beijing． |
| B．Some kinds of plants aren’t affected by air pollution． |
| C．Crops in China are hard to feed its large population． |
| D．People should stop developing economically |
According to the passage，the Chinese govemment should
| A．care more about developing economy |
| B．reduce the number of cars and industries |
| C．continue to make more researches |
| D．take measures to reduce carbon emissions |
What′S the best title of the passage?
| A．Polluted air damages plants and crops |
| B．Air pollution is becoming more serious |
| C．China’s air pollution and climate changes |
| D．Food security in China |
What if I took that big jump on my bike?What’s the worst thing that could happen if I go out at midnight?Should try smoking?The teen years can play out like a choose-your-own-adventure novel.
Teenagers must act on an endless parade of choices.Some choices.including smoking.Come with serious consequences.As a result, adolescents often find themselves trapped between their impulsive tendencies（-Just try it!)and their newfound ability to make well-informed and logical choices（-Wait, maybe that’s not such a good idea!）.
So what makes the teenager’s brain so complex? What drives adolescents-more than any other age group-to sometimes make rash or questionable decisions?
If you have ever thought that the choices teenagers make are all about exploring and pushing limits, you are on to something. Experts Experts believe that this tendency marks a necessary period in teen development.The process helps prepare teenagers to confront the world on their own. It is something all humans have evolved to experience-yes, teens everywhere go through this exploratory period.Nor is it unique to people:Even laboratory mice experience a similar stage during their development.
For example，laboratory experiments show that young mice stay close by their mothers for safety. As mice grow．their behavior does too．“When they reach puberty，they’re like，‘I’m gonna start checking out how this environment looks without my mom，…explains Beatriz Luna,of the University of Pittsburgh．
As a developmental cognitive neuroscientist，Luna studies those changes that occur in the brain as children develop into adults．She and other researchers are showing how the teen experience can lead to powerful advantages later in life．Take mice again：Young mice that explore most tend to live longest——that is，unless a cat eats them，Luna adds．What is the best title for the text?
| A．Teenagers make endless choices |
| B．The teenage brain drives them to be different |
| C．How the teenage brain develops |
| D．Researches about the teenagers |
What does the underlined sentence in paragraph 4 mean?
| A．It means “you are wrong”. |
| B．It means“you lose your way”． |
| C．It means“you get the point”． |
| D．It means“you are off the point”. |
According to the text,the teenager who explores most wiIl
| A．make no mistakes in his life． |
| B．have advantages over others. |
| C．loSe his confidence even his life. |
| D．experience no failure and live Iongest. |
What does the writer want to tell us by taking mice for example？
| A．young mice try to look for safety. |
| B．Young mice like to stay with their mothers. |
| C．Mice also experience a period to explore the world. |
| D．Mice experience different stages. |
What may the text discuss in the next part?
| A．How call a teenager make right choices |
| B．Why the parents shouldn’t allow teenagers to smoke |
| C．What has been discovered in the lab experiment． |
| D．What really goes on in the teenage brain. |
If you haven’t seen or heard anything about Road Rage in the last few months, you’ve probably been avoiding the media. There have been countless stories about this new and scary phenomenon, considered a type of aggressive driving. You have most likely encountered aggressive dnriving or Road Rage recently if you drive at all.
While drunk driving remains a critical problem，the facts about aggressive driving are surely as disturbing. For instance，according to the National Highway Transportation Safety Association, 41，907 people died on the highway last year．of those deaths,the agency estimates that about two-thirds were caused at least in part by aggressive driving behavior．
Why is this phenomenon occurring more than ever now and why is it something that seemed almost nonexistent a few short years ago?Experts have certain theories，and all are probably partially correct．One suggestion is over crowding．In the last decade，the number of the cars on the roads has increased by more than 11 percent，and the number of miles driven has increased by 35 percent．However,the number of new road miles has only increased by 1 percent．That means more cars in the same amount of space；and the problem is even serious in urban areas．Also，people have less time and more things to do．With people working and trying to fit extra chores and activities into the day，street levels have never been higher．Stress creates anxiety,which leads to short tempers．These factors，when combined in certain situations，Can induce Road Rage.
You may think you are the last person who would drive aggressively，but you might be surprised．For instance, have you ever yelled out loud at a slower driver,sounded the horn long and hard at another car, or sped up to keep another driver from passing?If you recognize yourself in any of these situations，watch out!
Whether you are getting angry at other drivers，or another driver is visibly upset with you，there are things you can do to avoid any major conflict.If you are easily influenced to Road Rage，the key is to discharge your emotion in a healthy way.If You are the target of another driver’s rage，do everything possible to get away from me other drive safely，including avoiding eye contact and getting out of their way． www.sdzxlm.comWhat can we learn from the first paragraph?
| A．Most people are angry at media reports and want to avoid them |
| B．Most drivers have bad manners |
| C．Road Rage has received much media attention in the past few months |
| D．People showing no interest in the media know little about recent happenings |
According to the passage，what are the causes of overcrowding?
| A．Stress，anxiety and short tempers． |
| B．People working together in a big city． |
| C．More cars stopping in the same amount of space |
| D．Quickly increasing cars and slowly increasing new road miles |
The underlined“induce”in Paragraph3 Call be replaced by“
| A．relax | B．cause | C．reduce | D．destroy |
Which of the following is“aggressive driving”?
| A．Phoning while driving． |
| B．Driving at a low speed． |
| C．Shouting loud at another driver． |
| D．Sounding the horn when driving． |
What does the writer want to tell US by writing the last paragraph?
A．Flow to control our anger
B．How to deal with Road Rage．
C，How to recognize aggressive drivers．
D．How to avoid eye contact with other drivers．
Motown songwriter-producer Deke Richards，who was behind songs including The Jackson 5's first three US number one hits，has died aged 68．
Richards，who had oesophageal(食管的)cancer,died in a Washington state hospice(安养院)，Universal Music said．The musician，whose real name was Dennis Lussier,Was leader of the Motown songwriting，arranging and producing team—The Corporation．Their hits include The Jackson 5'S I Want You Back and ABC．
Richards also co-wrote Love Child for Diana Ross and The Supremes，as well as Ross’s solo track I’m Still Waiting.He produced and wrote for Martha Reeves and the Vamlellas and Bobby Darin．
The Corporation，which consisted of Motown label head Berry Gordy,Alphonzo Mizell，Freddie Perren and Richards，was set up in 1969 to create hit records for the label’s new act，The Jackson 5．
They also wrote，produced and arranged the band’s singles and Maybe Tomorrow and Mama's Pearl．
According to Michael Jackson biographer,J．Randy Taraborrelli，Mama’s Pearl was originally called Guess Who’S Making Whoopie(With Your Girlfriend)．
But Richards had the lyrics changed to preserve the young frontman’s innocent image．
The Hollywood Reporter said Richards' "love of music” kept him involved with a variety of projects，including last year’S production of The Jackson 5's Come and Get It：The Rare Pearls．featuring rare and unreleased(未发行的) tracks．
Richards’ final work was the mixing of eight unreleased tracks by Martha Reeves and The Vandellas for the band's 50th anniversary box set,which is to be released on 5 April．Deke Richard wrote songs for the following singers EXCEPT
| A．Martha Reeves | B．Joan Lussier | C．Bobby Darin | D．Jackson 5’s |
Which of the following is true about Richards?
| A．He died at the age of68 in a Washington clinic． |
| B．He is a musician behind many hit songs. |
| C．He wrote“I’m Still Waiting”for Martha Reeves． |
| D．His final work is to be released in May. |
What Call we learn from the passage?
| A．The Corporation has a history of more than 40 years． |
| B．The lyrics of Mama’S Pearl turned out to be a failure． |
| C．The lyrics of Mama’S Pearl Was changed by J．Randy Taraborrelli． |
| D．Richards said his own love of music kept him involved with many projects． |
It is implied in the passage that______．
| A．Richards hardly co-wrote songs for singers |
| B．the Jackson 5's Come and Get it Was left unfinished as Richards got i11． |
| C．The corporation Was set up to earn money． |
| D．Richards had deep love for music． |
Which column can you most possibly find the passage on a website?
| A．Health | B．Business | C．Technology | D．Entertainment |
In times of economic crisis, Americans turn to their families for support. If the Great Depression is any guide, we may see a drop in our skyhigh divorce rate. But this won’t necessarily represent an increase in happy marriages. In the long run, the Depression weakened American families, and the current crisis will probably do the same.
We tend to think of the Depression as a time when families pulled together to survive huge job losses. By 1932, when nearly one-quarter of the workforce was unemployed, the divorce rate had declined by around 25% from 1929. But this doesn’t mean people were suddenly happier with their marriages. Rather, with incomes decreasing and insecure jobs, unhappy couples often couldn’t afford to divorce. They feared neither spouse could manage alone.
Today, given the job losses of the past year, fewer unhappy couples will risk starting separate households. Furthermore, the housing market meltdown will make it more difficult for them to finance their separations by selling their homes.
After financial disasters family members also tend to do whatever they can to help each other and their communities. A 1940 book “The Unemployed Man and His Family”, described a family in which the husband initially reacted to losing his job “with tireless search for work.” He was always active, looking for odd jobs to do.
The problem is that such an impulse is hard to sustain. Across the country, many similar families were unable to maintain the initial boost in morale(士气). For some, the hardships of life without steady work eventually overwhelmed their attempts to keep their families together. The divorce rate rose again during the rest of the decade as the recovery took hold.
Millions of American families may now be in the initial stage of their responses to the current crisis, working together and supporting one another through the early months of unemployment.
Today’s economic crisis could well generate a similar number of couples whose relationships have been irreparably(无法弥补地)ruined. So it’s only when the economy is healthy again that we’ll begin to see just how many broken families have been created.In the initial stage, the current economic crisis is likely to __________.
| A．tear many troubled families apart |
| B．bring about a drop in the divorce rate |
| C．contribute to enduring family ties |
| D．cause a lot of conflicts in the family |
In the Great Depression many unhappy couples chose to stick together because_______.
| A．starting a new family would be hard |
| B．they expected things would turn better |
| C．they wanted to better protect their kids |
| D．living separately would be too costly |
In addition to job losses. What stands in the way of unhappy couples getting a divorce?
| A．Mounting family debts |
| B．A sense of insecurity |
| C．Falling housing prices |
| D．Difficulty in getting a loan |
What will the current economic crisis eventually do to some married couples?
| A．It will irreparably damage their relationship |
| B．It will undermine their mutual understanding |
| C．It will help strengthen their emotional bonds |
| D．It will force them to pull their efforts together |
What can be inferred from the last paragraph?
| A．The economic recovery will see a higher divorce rate |
| B．Few couples can stand the test of economic hardships |
| C．A stable family is the best protection against poverty. |
| D．Money is the foundation of many a happy marriage |
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