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 may feel extremely tired for several days. They may also have problems 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 young 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 (紧张). 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 (永久性的) affect memory.

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

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

From the result of the research we can see that _________.

A. the women who have longer rest at home show better memory

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 less hormones

What is the subject discussed in the text?

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.

More than half of Americans do not take all their vacation days，even though they think they need one more holiday.And nearly a third of workers who take a break check their e-mails from the boss every other day and some even keep in touch hourly.

“We’re workaholics(工作狂)’，”said Samuel Nahmias.“From a general perspective，this has a lot to do with the economic situation in the US.More and more people are unemployed.”

With jobless numbers reaching 9.6 percent，people who have jobs seem to be unwilling to take time off.“It_is_not_a_great_picture and that affects vacations.People are not going on vacation as much and those who are going on vacation are being more selective about where they are going.”Nahmias explained.

Unlike European countries where four or more weeks of holiday each year is normal,27 percent of people questioned in the poll said they had 6 to 10 days of annual leave and 20 percent had less than 3 days.With more people on unemployment lists in America，those still with jobs are facing more responsibility at work，which is reflected in their lack of time off.

The majority of workers who did not take time off mentioned too many responsibilities or stress at work，while some people said they simply did not have time to plan a holiday.“People are more conscious of what they are doing and when they are going on vacation because they don’t want to look bad in this situation，”Nahmias explained.

Technology is also playing a part with smartphones enabling workers to keep in contact in ways that were not possible before.It has to do with technology and the level of concern about what is going on in the office.

1．Americans don’t take all their vacation days because ________.

A．they devote themselves to the whole work

B．they are afraid that they may lose their jobs

C．they are asked to keep in touch with their bosses

D．they aren’t in need of holidays at all

2．What does Nahmias mean by saying the underlined words in Paragraph 3?

A．Travelling makes people unwelcome.

B．People are unwilling to go on short vacations.

C．The economic situation remains at a low point.

D．People are more selective about places of interest.

3.We can infer from Paragraph 4 that ________.

A．Unemployment rate is higer in America than that in Europe

B．European economic situation is better than that in America

C．Americans are more hard-working than Europeans

D．More people are losing their jobs in Europe

4．What’s the main idea of the text?

A．Americans are all workaholic.

B．Many Americans don’t choose to take vacations.

C．Unemployment is going from bad to worse.

D．US economic situation becomes worse and worse.

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. Jet lag interferes with a person's normal times for sleeping and waking. People with jet lag may feel extremely tired for several days. They also may have problems thinking clearly and remembering.

Kwangwook Cho is a researcher at the University of Bristol in Britain. He reported the findings of his jet lag study in the publication Nature Neuroscience.

The study involved twenty young women who worked for international airlines. The women 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.

Mister Cho took some fluid from the women's mouths to measure levels of a hormone 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 using magnetic resonance imaging. This is a way to measure the size of the brain's temporal lobes（颞叶）.

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.

Mister Cho says he 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.

1.According to the text, jet lag _____.

    A. can cause difficulties in speaking

    B. can make people feel tired for a few weeks

    C. is the illness only found in people who work on the airplanes

    D. can be caused by flying over several time zones in an airplane

2.It is inferred that more tests need to be done because _____.

    A. the conclusion was questioned by many scientists

    B. scientists fear that his research is not done properly

    C. every scientific conclusion needs the support from many tests

    D. the woman who were studied in the research were not healthy

3.Which of the following statements is TRUE about the research results?

    A. Women who have a longer rest at home show better memory.

    B. Women who fly in short time had smaller right temporal lobes.

    C. Women who have longer flights failed the memory test.

    D. Women who rest more than 14 days produced less hormones.

4.What is the subject discussed in the test?

    A. The cause of jet lag.

    B. A story of a group of flight attendance.

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

    D. The importance of having enough rest after long flights.

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. Jet lag interferes with a person's normal times for sleeping and waking. People with jet lag may feel extremely tired for several days. They also may have problems thinking clearly and remembering.

Kwangwook Cho is a researcher at the University of Bristol in Britain. He reported the findings of his jet lag study in the publication Nature Neuroscience.

The study involved twenty young women who worked for international airlines. The women 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.

Mister Cho took some fluid from the women's mouths to measure levels of a hormone 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 using magnetic resonance imaging. This is a way to measure the size of the brain's temporal lobes（颞叶）.

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.

Mister Cho says he 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.

72. According to the text, jet lag _____.

       A. can cause difficulties in speaking

       B. can make people feel tired for a few weeks

       C. is the illness only found in people who work on the airplanes

       D. can be caused by flying over several time zones in an airplane

73. It is inferred that more tests need to be done because _____.

       A. the conclusion was questioned by many scientists

       B. scientists fear that his research is not done properly

       C. every scientific conclusion needs the support from many tests

       D. the woman who were studied in the research were not healthy

74. Which of the following statements is TRUE about the research results?

       A. Women who have a longer rest at home show better memory.

       B. Women who fly in short time had smaller right temporal lobes.

       C. Women who have longer flights failed the memory test.

       D. Women who rest more than 14 days produced less hormones.

75. What is the subject discussed in the test?

       A. The cause of jet lag.

       B. A story of a group of flight attendance.

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

       D. The importance of having enough rest after long flights.

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 may feel extremely tired for several days . They may also have problems 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 young 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 . Halt 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 (唾液) 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 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 .

57．According to the text , jet lag        .

       A．can cause difficulties in speaking

       B．can be caused by flying over several time zones

       C．can be only found in flight attendants

       D．can make people feel tired for a few weeks

58．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

59．From the result of the research we can see that        .

      A．the women who have longer rest at home show better memory

       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

60．What is the subject discussed in the text ?

       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 .