Everybody hates rats．But in the earthquake capitals of the world-Japan，Los Angeles，Turkey-rats will soon be man's new best friends．

What happens after an earthquake? We send in rescue（救援） dogs. Why? Because they can smell people．Dogs save lives．They help rescuers to find living people．But dogs are big and they can't get into small spaces．So now a new research project is using a smaller animal to save lives：the rat．

How does it work? First，the rat is trained to smell people．When this happens，the rat's brain gives a signal（信号）．This is sent to a small radio on its back，and then the rescuers follow the radio signals．When the rat's brain activity jumps，the rescuers know that someone is alive．The rat has smelled that person．

Although there are already robots which can do this job，rats are better．Christian Linster at Cornell University—New York says，“Robots' noses don't work well when there are other smells around．Rats are good at that．” Rats can also see in the dark．They are cheaper and quicker to train than dogs，and unlike robots，they don't need electricity!

The “rat project” is not finished，but Julie Ryan of International Rescue Corps in Scotland says，“It would be fantastic．A rat could get into spaces we couldn't get to and a rat would get out if it wasn't safe．” Perhaps for the first time in history，people will be happy to see a rat in a building（but only after an earthquake，of course）．

1.In the world earthquake capitals，rats will become man's best friends because they can _________．

A. take the place of man's rescue jobs

B. find the position of people alive who are trapped in buildings

C. serve as food for people alive who are trapped in buildings

D. get into small spaces

2.From the third paragraph we know the rescuers can judge a person is alive by_________．

A. the noise made by the rat                    B．the rat's unusual behavior

C. the signal sent by the radio on the rat's back   D．the smell given off by the person

3. In doing rescue jobs，_________．

A. rats smell better than dogs

B. dogs don't need to be trained to smell people

C. robots' sense of smell can be affected by other smells around

D. rats can see in the dark and smaller than robots

4. Rats have all the following advantages except that_________．

A. they are more fantastic than other animals       B. they are less expensive to train than dogs

C. they don't need electricity                  D. they are small and can get into small places

Motherhood may make women smarter and may help prevent dementia （痴呆） in old age by bathing the brain in protective hormones （荷尔蒙） , U.S. researchers reported on Thursday.
Tests on rats show that those who raise two or more litters of pups do considerably better in tests of memory and skills than rats who have no babies, and their brains show changes that suggest they may be protected against diseases such as Alzheimer’s （早老痴呆症）. University of Richmond psychology professor Craig Kinsley believes his findings will translate into humans.
“Our research shows that the hormones of pregnancy are protecting the brain, including estrogen （雌激素）, which we know has many neuroprotective （保护神经的） effects,” Kinsley said.
“It’s rat data but humans are mammals just like these animals are mammals,” he added in a telephone interview. “They go through pregnancy and hormonal changes.”
Kinsley said he hoped public health officials and researchers will look to see if having had children protects a woman from Alzheimer’s and other forms of age-related brain decline.
“When people think about pregnancy, they think about what happens to babies and the mother from the neck down,” said Kinsley, who presented his findings to the annual meeting of the Society of Neuroscience in Orlando, Florida.
“They do not realize that hormones are washing on the brain. If you look at female animals who have never gone through pregnancy, they act differently toward young. But if she goes through pregnancy, she will sacrifice her life for her infant—that is a great change in her behavior that showed in genetic alterations （改变） to the brain.”
【小题1】 How do scientists know “Motherhood may make women smarter”?

Scientists in Colombia have trained a team of rats to help remove land mines from the countryside. Land mines are small bombs hidden in the ground and designed to explode(爆炸) when someone steps on them.

When trained, the rats can smell special metals in the mines and then signal(发信号) to their human team. Then why use rats for such an important job?

In the past, dogs have been used to find bombs. Rats have a good sense of smell and can respond to orders, just like dogs do. But rats are much lighter than dogs. They stand less of a chance of setting off the mines, which explode under a certain amount of weight. What’s more, the best rats are cheaper to keep than dogs. It costs about the same amount of money to take care of one dog as it does 70 rats.

The rats have already been used in Tanzania, an African country with many land mines. Luisa Fernanda Méndez and her team in Colombia are training the even lighter Wistar rats. These are the white rats with red eyes that scientists often use in laboratory experiments. “They even train their babies to perform their jobs, which saves us a lot of time, ” Méndez said.

Colombia has the second-highest rate(比率) of deaths from land mine accidents in the world. Last year, land mines killed 695 people — 56 of whom were children. A criminal group called the Revolutionary Armed Forces of Colombia, or FARC, as well as other organizations, have placed the mines. FARC are strongly against Colombia’s government. The group has placed mines all around its own bases and in many places in the countryside.

In the past, the Colombian government hired peasants and poor farmers to find mines. Many of them died trying to find the well-hidden bombs.

Colombian police official Erick Guzmán hopes the team of rats can come to the rescue(援救). “These rats will be a great help,” he said.

1.How do rats help to find land mines?

A．By their special sight.                     B．By their light weight.

C．By their sense of smell.                   D．By their excellent hearing.

2.The advantage of rats over dogs in finding bombs is that _____.

A．they are cleverer.

B．they run faster

C．they have a better sense of smell

D．they don’t make mines explode as easily

3.The underlined word “They” may refer to ______.

A．scientists                              B．Wistar rats

C．dogs                                 D．Méndez and her team

4. What is the passage mainly about?

A．Specially-trained rats help clear land mines.

B．People in Tanzania are suffering from land mines.

C．Dogs are no longer used to find land mines.

D．Land mines have become a great danger to Colombians.

The high noise of modern life may affect speech and language development in the very young, according to a study that found the auditory (听觉的) parts of the brains of young mice are slower to organize properly in the presence of continuous sounds.

Researchers at the University of California, San Francisco, reared a group of rats in an environment of continuous background noise and found that their brain circuits that receive and interpret (解释) sound did not develop at the same rate as animals that were raised in a quieter environment.?

Edward F. Chang and Michael Merzenich, co-authors of the study appearing in the journal Science, said that the continuous noise delayed the organization of auditory neurons (神经细胞) during a critical two-to-three-week period after the rat pups were born.?

For rats not exposed to the noise, the auditory cortex(皮层) neurons during this period gathered into a smaller area and began developing a selective response to sounds.?

But for the noise?exposed rats, this organization was slowed, causing a delay in the development of the ability to discriminate(辨别) specific sound tones. The researchers said it took three or four times longer for the rats raised in a noisy environment to reach the basic bench marks (基准) of auditory development seen in the rat pups not exposed to noises.?

Although the rat is not a perfect model for what happens in humans, the authors note, the study does suggest that high levels of noise might possibly affect some language learning in babies.?

“These findings suggest that environmental noise, which is commonly present in contemporary child-rearing environments, can potentially contribute to auditory and language-related development delays,”the authors wrote in Science.?

The authors noted that although the brain development was delayed in rats exposed to the noise, their brains did eventually mature (成熟的) normally.?

The scientists at California University studied rats_______.?

A. of different age groups     B. with different habits?

C. in different environments  D. from different areas?

The rats exposed to noise, compared to those not exposed, _______.?

A. were more sensitive   B. were duller?

C. grew up more slowly D. gathered together more quickly

The result of the research mainly tells us that noise _______.

A. delays brain development  B. stops baby growth

C. affects speech and language      D. destroys brains?

Everybody hates rats．But in the earthquake capitals of the world-Japan，Los Angeles，Turkey-rats will soon be man's new best friends．
What happens after an earthquake? We send in rescue（救援） dogs. Why? Because they can smell people．Dogs save lives．They help rescuers to find living people．But dogs are big and they can't get into small spaces．So now a new research project is using a smaller animal to save lives：the rat．
How does it work? First，the rat is trained to smell people．When this happens，the rat's brain gives a signal（信号）．This is sent to a small radio on its back，and then the rescuers follow the radio signals．When the rat's brain activity jumps，the rescuers know that someone is alive．The rat has smelled that person．
Although there are already robots which can do this job，rats are better．Christian Linster at Cornell University—New York says，“Robots' noses don't work well when there are other smells around．Rats are good at that．” Rats can also see in the dark．They are cheaper and quicker to train than dogs，and unlike robots，they don't need electricity!
The “rat project” is not finished，but Julie Ryan of International Rescue Corps in Scotland says，“It would be fantastic．A rat could get into spaces we couldn't get to and a rat would get out if it wasn't safe．” Perhaps for the first time in history，people will be happy to see a rat in a building（but only after an earthquake，of course）．
【小题1】In the world earthquake capitals，rats will become man's best friends because they can _________．