A new study says one part of the human brain may become smaller as the result of a condition known as jet lag. Jet lag results from flying long distances in an airplane. People with jet lag feel extremely tired for several days. They may also have problems in thinking clearly and remembering.

Recently a researcher at the University of Bristol in Britain reported the findings of his jet lag study, which involved twenty women who worked for international airlines. They had served passengers on airplanes for five years. These flight attendants flew across many countries and at least seven time zones. In the study, the flight attendants had different amounts of time to recover from jet lag. Half the women spent five days or fewer in their home areas between long flights. The other half spent more than fourteen days in their home areas.

The researcher took some saliva from the women’s mouths to measure levels of a hormone  (荷尔蒙 ) that increases during stress . He tested them to see if they could remember where black spots appeared on a computer screen .And he took pictures of their brains to measure the size of the brain’s temporal lobes. (脑叶).

It was found that the women who had less time between flights had smaller right temporal lobes. This area of the brain deals with recognizing and remembering what is seen. The same group performed worse and had slower reaction times on the visual memory test. And their saliva samples showed higher levels of stress hormones.

The researcher believes the brain needs at least ten days to recover after a long trip. He says airline workers told him their ability to remember got worse after working on planes for about four years. Other studies have shown that increased feelings of stress can cause a loss of cells in the part of the brain that controls memory.

Scientists say more tests are needed to study the effects of jet lag on the brain. They want to find out if too much jet lag could permanently affect memory.

47．According to the text, jet lag _____.

A. can cause difficulties in speaking  

B. can make people feel tired for a few weeks

C. can be only found in flight attendants

D. can be caused by flying over several time zones

48．It can be inferred from the text that ______.

A. the conclusion is refused by many scientists

B. scientists fear that this research is not done properly

C. every scientific conclusion needs the support from many tests

D. the women who were examined in the research were not healthy

49．From the result of the research we can see that _____.

A. the women who have longer rest at home perform better on the test.

B. the women who fly in short time have smaller right temporal lobes

C. the women who have longer flights fail the memory test

D. the women who rest more than 14 days produce more hormones

50．What is the subject discussed in the test?

A. The cause of jet lag.

B. A story of a group of flight attendants.

C. The importance of having enough rest after flights.

D. A research about the effects of jet lag on the brain.

Had you devoted _______ energy to your lessons，you would have been ______ disappointed．

A．more；less           B．fewer；more          C．least；most             D．most；least

THIS was the year the Earth struck back.

Earthquakes, heat waves, floods, volcanoes, super typhoons, snow storms, landslides and droughts killed at least a quarter of a million people in 2010 – the deadliest year in more than a generation. More people were killed worldwide by natural disasters this year than have been killed in terrorism attacks in the past 40 years combined.

"It just seemed like it was back-to-back and it came in waves," said Craig Fugate, who heads the U.S. Federal Emergency Management Agency. It handled a record number of disasters in 2010.

And we have ourselves to blame most of the time, scientists and disaster experts say.

Even though many catastrophes have the ring of random chance, the hand of man made this a particularly deadly, costly, extreme and weird（古怪的） year for everything from wild weather to earthquakes.

Poor construction and development practices conspire to make earthquakes more deadly than they need be. More people live in poverty in vulnerable（脆弱的） buildings in crowded cities. That means that when the ground shakes, the river breaches, or the tropical cyclone hits, more people die.

Disasters from the Earth, such as earthquakes and volcanoes "are pretty much constant," said Andreas Schraft, vice president of catastrophic perils for the Geneva-based insurance giant Swiss Re. "All the change that's made is man-made."

The January earthquake that killed well more than 220,000 people in Haiti is a perfect example. Port-au-Prince has nearly three times as many people - many of them living in poverty - and more poorly built shanties than it did 25 years ago. So had the same quake hit in 1985 instead of 2010, total deaths would have probably been in the 80,000 range, said Richard Olson, director of disaster risk reduction at Florida International University.

In February, an earthquake that was more than 500 times stronger than the one that struck Haiti hit an area of Chile that was less populated, better constructed, and not as poor. Chile's bigger quake caused fewer than 1,000 deaths.

Climate scientists say Earth's climate also is changing, bringing extreme weather, such as heat waves and flooding.

In the summer, one weather system caused oppressive heat in Russia, while farther south it caused flooding in Pakistan that inundated 161,200 square kilometers, about the size of Wisconsin. That single heat-and-storm system killed almost 17,000 people, more people than all the worldwide airplane crashes in the past 15 years.

Scientists have calculated that the killer Russian heat wave—setting a national record of 43.9℃—would happen once every 100,000 years without global warming.

What is responsible for the most human deaths in 2010?

A．Natrual disasters.       B．Terrorist attacks.

    C．Poor buildings.      D．Too rapid developrnent.

According to Andreas Schraft,             .

A．earthquakes are happening more often because of human beings

B．earthquakes are causing more damage because of human beings

C．stronger houses should be built to limit storm damage

D．Port—au—Prince is now overpopulated

The main point of the article is to           

A．list the natural disasters that occurred in 2010

B．give the details of some natural disasters of 2010

C．warn that more natural disasters are to strike

D．blame humanity for not helping those affected by the disasters

THIS was the year the Earth struck back.

Earthquakes, heat waves, floods, volcanoes, super typhoons, snow storms, landslides and droughts killed at least a quarter of a million people in 2010 – the deadliest year in more than a generation. More people were killed worldwide by natural disasters this year than have been killed in terrorism attacks in the past 40 years combined.

"It just seemed like it was back-to-back and it came in waves," said Craig Fugate, who heads the U.S. Federal Emergency Management Agency. It handled a record number of disasters in 2010.

And we have ourselves to blame most of the time, scientists and disaster experts say.

Even though many catastrophes have the ring of random chance, the hand of man made this a particularly deadly, costly, extreme and weird（古怪的） year for everything from wild weather to earthquakes.

Poor construction and development practices conspire to make earthquakes more deadly than they need be. More people live in poverty in vulnerable（脆弱的） buildings in crowded cities. That means that when the ground shakes, the river breaches, or the tropical cyclone hits, more people die.

Disasters from the Earth, such as earthquakes and volcanoes "are pretty much constant," said Andreas Schraft, vice president of catastrophic perils for the Geneva-based insurance giant Swiss Re. "All the change that's made is man-made."

The January earthquake that killed well more than 220,000 people in Haiti is a perfect example. Port-au-Prince has nearly three times as many people - many of them living in poverty - and more poorly built shanties than it did 25 years ago. So had the same quake hit in 1985 instead of 2010, total deaths would have probably been in the 80,000 range, said Richard Olson, director of disaster risk reduction at Florida International University.

In February, an earthquake that was more than 500 times stronger than the one that struck Haiti hit an area of Chile that was less populated, better constructed, and not as poor. Chile's bigger quake caused fewer than 1,000 deaths.

Climate scientists say Earth's climate also is changing, bringing extreme weather, such as heat waves and flooding.

In the summer, one weather system caused oppressive heat in Russia, while farther south it caused flooding in Pakistan that inundated 161,200 square kilometers, about the size of Wisconsin. That single heat-and-storm system killed almost 17,000 people, more people than all the worldwide airplane crashes in the past 15 years.

Scientists have calculated that the killer Russian heat wave—setting a national record of 43.9℃—would happen once every 100,000 years without global warming.

1.What is responsible for the most human deaths in 2010?

A．Natrual disasters.                                      B．Terrorist attacks.

    C．Poor buildings.                      D．Too rapid developrnent.

2.According to Andreas Schraft,             .

A．earthquakes are happening more often because of human beings

B．earthquakes are causing more damage because of human beings

C．stronger houses should be built to limit storm damage

D．Port—au—Prince is now overpopulated

 

3.The main point of the article is to           

A．list the natural disasters that occurred in 2010

B．give the details of some natural disasters of 2010

C．warn that more natural disasters are to strike

D．blame humanity for not helping those affected by the disasters