How would you like to sleep with one half your brain asleep and the other half awake? Dolphins sleep this way. Recently, scientists at Indiana State University have discovered that ducks sleep this way too. They found that ducks sleep half awake so they can rest and watch for danger at the same time.

After putting their ducks in a row and videotaping them, some researchers found ducks on the end of each row spent more time asleep with one eye open, apparently looking for predators.

“The more the ducks felt threatened ,the more they slept with one eye open,” said lead author Niels C．Rattenborg, a graduate student at Indiana State University, Terre Haute.” the unique aspect is not that they do it, but that they control it. When they sleep at the edge of a group, they tend to realize greater danger, so they spend more time sleeping with one half of their brain.” Ducks with one eye open were still awake enough to detect predators, said the authors of the study, which appears today in the Journal Nature.

The researchers studied four groups of four ducks held in plastic boxes, which were arranged in a row. Ducks on the end were found to sleep with one eye open 31.8 per cent of the time, compared to 12.4 percent of the time for ducks in the central position.

Also, ducks in the central position did not open one eye more than the others, while ducks on each end kept the eye facing away from the group open 86.2 per cent of the time. Brain wave readings of the ducks showed that the half of the brain receiving signals from the closed eye indicated that half of the brain was sleeping. Signals from the half of the brain receiving signals from the open eye showed a state between fully awake and asleep.

1．A predator is most likely to be       .

       A．a scientist who does research work on animals

       B．a human being who looks after and feeds ducks

       C．an animal that hunts ,kills and eats other animals

       D．an animal that is likely to be friends with ducks

2．Ducks at the end of each row sleep with one eye open because    .

       A．they are looking for food

       B．they want to enjoy the scenery

       C．they are watching out for danger

       D．they are unique in their sleeping habit

3．How many ducks were used in the experiment?

       A．Four.                  B．Eight.                  C．Twelve.               D．Sixteen.

4．Which of the following is true according to the passage?

       A．Ducks on the northern end of a row would keep their eye facing the south open.

       B．Ducks with less sense of duty usually choose to stay in the center of a row.

       C．Ducks with one eye open at the edge can still enjoy a certain degree of sleep.

       D．A video tape recorder was the only electronic device used in the experiment.

How would you like to sleep with one half your brain asleep and the other half awake? Dolphins sleep this way. Recently , scientists at Indiana State University have discovered that ducks sleep this way too. They found that ducks sleep half awake so they can rest and watch for danger at the same time.

After putting their ducks in a row and videotaping them, some researchers found ducks on the end of each row spent more time asleep with one eye open ,apparently looking for predators.

“The more the ducks felt threatened ,the more they slept with one eye open,” said lead author Niels C. Rattenborg ,a graduate student at Indiana State University ,Terre Haute .”the unique aspect is not that they do it ,but that they control it . When they sleep at the edge of a group ,they tend to realize greater danger ,so they spend more time sleeping with one half of their brain.” Ducks with one eye open were still awake enough to detect predators ,said the authors of the study ,which appears today in the journal Nature.

 The researchers studied four groups of four ducks held in plastic boxes ,which were arranged in a row .Ducks on the end were found to sleep with one eye open 31.8 per cent of the time, compared to 12.4 percent of the time for ducks in the central position.

Also ,ducks in the central position did not open one eye more than the others, while ducks on each end kept the eye facing away from the group open 86.2 per cent of the time. Brain wave readings of the ducks showed that the half of the brain receiving signals from the closed eye indicated that half of the brain was sleeping. Signals from the half of the brain receiving signals from the open eye showed a state between fully awake and asleep.

71．It was discovered that      .

       A．most people would like to be half asleep

       B．ducks can sleep half awake

       C．dolphins sleep on their way

       D．ducks have different sleeping habits from each other

72．A predator is most likely to be       .

       A．an animal that hunts ,kills and eats other animals

       B．a human being who looks after and feeds ducks

       C．a scientist who does research work on animals

       D．an animal that is likely to be friends with ducks

73．Ducks at the end of each row sleep with one eye open because    .

       A．they are looking for food                     

       B．they want to enjoy the scenery

       C．they are watching out for danger          

       D．they are unique in their sleeping habit

74．How many ducks were used in the experiment?

       A．Four.                  B．Eight.                  C．Twelve.               D．Sixteen.

75．Which of the following is true according to the passage?

       A．Ducks on the northern end of a row would keep their eye facing the south open.

       B．Ducks with less sense of duty usually choose to stay in the center of a row.

       C．Ducks with one eye open at the edge can still enjoy a certain degree of sleep.

       D．A video tape recorder was the only electronic device used in the experiment.

  

　　Bird flu(禽流感) has puzzled scientists by striking millions of chickens in several Asian countries within a very short period of time, with the worst hit areas in Thailand. China and Viet Nam and by February 10,2004 at least 13 people were reported to have died.

　　The following is a chronology of the most recent bird flu outbreak in Asia, which also suffered outbreaks in 1997 and 1998:

　　Dec. 15,2003－South Korea con firms(证实) a highly contagious(传染的) type of bird flu at a chicken farm near the capital, Seoul, and begins a mass killing of poultry(家禽) when the virus(病毒) rapidly spreads across the country.

　　Dec. 31, 2003－Taiwan reports its first case of the virus. It later destroys thousands of chickens suffering from a milder form of bird flu.

　　Jan. 8, 2004－Viet Nam confirms that bird flu has been found on many of its poultry farms.

　　Jan. 11, 2004－Japan says 6, 000 chickens have died of bird flu on a farm, and says it is the first time the disease has been confirmed in the country.

　　Jan. 13, 2004－The World Health Organization (WHO) confirms that the deaths of three people in Viet Nam are linked to bird flu.

　　Jan. 23, 2004－Cambodia confirms an outbreak of bird flu at a farm on the outskirts of Phnom Penh.

　　Jan. 25, 2004－Indonesia discovers an outbreak of bird flu among chickens but has no evidence that the disease has spread to humans. Pakistan says 2 million chickens have died of a mild form of bird flu.

　　Jan. 26, 2004－Thailand confirms the death of a six－year－old boy, its first human death from bird flu.

　　Jan. 27, 2004－The bird flu virus kills ducks in southern parts of China, which begins a killing of 14,000 birds to stop the spread. The agriculture ministry in Laos confirms bird flu in the area around Vientiane(万象).

　　Jan. 30, 2004－China says tests confirm the H5N1 virus in Hubei and Hunan provinces as well as the southern region of Guangxi.

　　Feb. 1, 2004－China's state television reports five more areas with suspected (可疑的) cases of bird flu in poultry. The WHO says two sisters have died in Viet Nam after contracting bird flu and they may have caught the virus from their brother, who had also died.

　　Feb. 2, 2004－An 18－year－old person dies of bird flu in Ho Chi Minh City, bringing to nine the fatalities(死亡事件) in Viet Nam A．Thai woman dies of bird flu, taking that country's toll from the virus to three. The total number of fatalities stands at 12.

1．In how many countries and regions is Asia has bird flu broken out by Feb. 2, 2004?

[　　]

2．What does the underlined word “chronology” probably mean?

[　　]

A．A list of events in the order in which they happen.

B．A list of dates.

C．All kinds of bird flu.

D．A list of countries where bird flu has broken out.

3．Which of the following is NOT true, according to the passage?

[　　]

A．Three people died of bird flu in Thailand.

B．Nine people died of bird flu in Viet Nam.

C．Tests confirm the H5N1 virus in eight areas in China.

D．Japan says it's the first time bird flu has broken out in the country.

4．What would be the best title for the passage?

[　　]

A．Millions of chickens killed in Asia

B．Many people dying of bird flu in Asia

C．Scientists finding out the cause of bird flu

D．Bird flu spreading in Asia