Winter begins in the north on December 22nd. People and animals have been doing what they always do to prepare for the colder months. Squirrels (松鼠), for example, have been busy gathering nuts from trees. Well, scientists have been busy gathering information about what the squirrels do with the food they collect.

They examined differences between red squirrels and gray squirrels in the American state of Indiana. The scientists wanted to know how these differences could affect the growth of black walnut (黑胡桃) trees. The black walnut is the nut of choice for both kinds of squirrels. The black walnut tree is also a central part of some hardwood forests.

Rob Swihart of Purdue University did the study with Jake Goheen, a former Purdue student now at the University of New Mexico. The two researchers estimate that several times as many walnuts grow when gathered by gray squirrels as compared to red squirrels. Gray squirrels and red squirrels do not store nuts and seeds in the same way. Gray squirrels bury nuts one at a time in a number of places. But they seldom remember where they buried every nut. So some nuts remain in the ground. Conditions are right for them to develop and grow the following spring. Red squirrels, however, store large groups of nuts above ground. Professor Swihart calls “death traps for seeds”.

Gray squirrels are native to Indiana. But Professor Swihart says their numbers began to decrease as more forests were cut for agriculture. Red squirrels began to spread through the state during the past century.

The researchers say red squirrels are native to forests that stay green all year, unlike walnut trees. They say the cleaning of forest land for agriculture has helped red squirrels invade Indiana. Jake Goheen calls them a sign of an environmental problem more than a cause.

【小题1】The study done by Rob Swihart and Jake Goheen is to ________.

A．find out the living conditions for squirrels

B．learn squirrels’ influence on black walnut trees

C．do something to get rid of squirrels

D．save the forests in the American state of Indiana

【小题2】The difference between gray squirrels and red squirrels mainly lies in ________.

A．the way they gather the walnut

B．the time they have winter sleep

C．the place they have winter sleep

D．the place they store the walnuts

【小题3】When Professor Swihart says “death traps for seeds”, he actually means that ________.

A．red squirrels eat more nuts than gray squirrels

B．gray squirrels and red squirrels will have severe fights

C．nuts above the ground will not develop into plants

D．seeds can be traps for other animals in the forest

【小题4】According to the passage, which of the following is true?

A．The black walnut is equally attractive to both gray and red squirrels.

B．Gray squirrels do more harm to the forest than red squirrels.

C．Red squirrels and gray squirrels have helped the spread of walnut trees.

D．The cleaning of forest land benefits red squirrels directly.

   Just like humans, birds rely on sound to communicate, too. Often, birds recognize their mates or young by sound rather than sight. Hungry young birds use begging calls to let their mothers know it is feeding time, and warning calls are other sounds given out frequently by the adults. In addition to all these regular calls, some male birds develop beautiful songs intended（打算）to attract the females.

A new study carried out by an American university shows that songbirds practice their songs even in their sleep. The research team discovered that the electrical brain activity of the birds that were asleep was similar to the brain activity produced when the birds were awake and singing. Clearly the bird stores a song after hearing it, then practices it later in its sleep. Scientists now believe the birds dream of songs to help them master the fine art of singing and that sleep plays a key role in the learning process！

It is commonly known that many songbirds learn to sing by listening to adult birds of the same species. If taught the song of an adult of another bird species, the chick grows up singing the new song and passes on the foreign song to its chicks. For instance, researchers carried out an experiment in which a male bullfinch（红腹灰雀）was raised by a female canary（金丝雀）. The bullfinch soon learned the canary's songs and when it was later mated to a female bullfinch, Mr. Bullfinch taught his children the canary's songs.

Early last year, a British survey of London's songbirds showed that the city's birds are losing their melodies. Birds could hardly hear one another over the traffic noise；as a result they had difficulty in learning songs and communicating with potential mates. And instead of copying the sweet notes of the adults, chicks were copying sounds, which they heard most often—namely car horns（喇叭）and mobile phones！

【小题1】What can we learn according to Paragraph 2？

A．Sleep helps songbirds master new songs.

B．Songbirds can even hear songs in their dreams.

C．The study was carried out by Australian scientists.

D．The brain activity of songbirds would stop in their sleep.

【小题2】Why does Mr. Bullfinch teach his children the canary's songs？

A．Because he wants to help them learn a foreign language.

B．Because he can't sing bulfinches' songs.

C．Because he wants to make them get along well with other birds.

D．Because the canary's songs are more attractive.

【小题3】What's the problem of the city's birds according to the passage？

A．They have lost their voices.

B．They are losing their habitats.

C．They are bothered by the city's noises.

D．They tend to refuse to learn songs from adults.

【小题4】What conclusion can we draw from the passage？

A．The city's birds can learn more songs.

B．All birds learn foreign songs during their life.

C．It may be difficult for the city's birds to find their mates.

D．Young birds can tell the difference between songs and noises.

The Beagle Brigade

Return to the United States from a trip abroad ,and your luggage will get inspected by the Beagle Brigade, a team of beagles and their human partners. Working with human partners, the beagles sniff out potential threats to American agriculture.

An orange or apple, for example, might have a Mediterranean fruit fly. Hams could carry a disease such as hog cholera. These and other pests could destroy farmers' crops and livestock. " Once we introduce something   that   is not part of the environment, there may not be any controls of it in the environment," notes Lisa Davis at the National Dog Detector Training Center in Orlando, Florida. "The best thing for us to do is prevent it from coming across the border and becoming established. "

When a beagle sniffs specific food smells, it signals its partners by siting there. The human officer then investigates. When the dog is right ——which happens 90 percent of the time ——it gets an edible（可食用的） treat.

"The dog is not out there working," explains Davis. " It's out there playing. It's a game to the dog. "The handlers give the beagles plenty of food and love. They make sure they get first-class medical attention, too. When the dogs finally retire after 9 to 11 years ,they will find caring homes for them. It's a dog's life indeed!

Their people partners work and study somewhat harder. As specialized quarantine（检疫） officers,most hold degrees in the biological sciences or related sciences.

How well does the Beagle Brigade do its job? " On average," notes Davis, " each year our 54 teams prevent around 75,000 prohibited , restricted items. Since even one infected item could cause widespread destruction, that's a great result for America's agricultural environment.

【小题1】According to the article, what is the problem with agricultural products brought into the United States by passengers traveling from abroad?

A．They generate similar types of food smells.

B．They are difficult to identify, even with trained dogs.

C．They must be inspected before being allowed to enter the country.

D．They may carry something that could harm the local agricultural environment.

【小题2】According to the article , how does the beagle signal that it has found a suspicious food product?

A．By barking at its partners.

B．By begging for a treat.

C．By sitting next to the item.

D．By playing a game.

【小题3】How is the beagle congratulated for finding a specific food product?

A．The handler praises it with a hug.

B．The beagle gets to play for a few hours.

C．The beagle gets to retire to a caring home.

D．The handler gives it an edible reward.

【小题4】In the article , how does the author support the use of the Beagle Brigade?

A．By providing statistics about the number of items detected by the dogs.

B．By showing that the dogs enjoy discovering prohibited items.

C．By pointing out that good homes are found for the dogs when they retire.

D．By praising the fact that the dogs work for a government agency.

阅读P18教材课文，用合适的单词(不超过三个)填入下列表格

Yeti，Bigfoot and the Wild Man of Shennongjia
What they are called	Where they are seen	What they ____3____	What they Why they look the same
Yeti	In the Himalayas	large，____4____ animal that walks on two feet like a ____5____； moving with amazing ____6____ and ___7___； large tracks more than 33 centimetres ____8____	linked to a common ___9___，an animal that lived in ___10___ some 300,000 years ago
Bigfoot	____1____ of the north­west of the USA
Wild Man in Shennongjia	In ___2___Hubei Province，China

 
1. __________
2. __________
3. __________
4. __________
5. __________
6. __________
7. __________
8. __________
9. __________
10. __________

   The sea is home to billions of plants and animals. Many live only near the sunlit surface. Oceanographers sort marine (海洋的) living beings by dividing them into two main groups: plants and animals.

There are two general types of plants found in the ocean, those having roots that grow in the ocean bottom and those not having roots which simply float around with water. The rooted plants in the ocean are only found in shallow waters because there is not enough sunlight to maintain photosynthesis (光合作用) in deeper waters. Since sunlight does not pass more than a few hundred feet into the ocean, most of the ocean is unable to support rooted plants.

The most plants in the ocean are known as phytoplankton (浮游植物群落) . These are usually single-celled, small floating plants that float throughout the surface waters of the ocean. To grow, phytoplankton need nutrients from the sea water and lots of sunlight.

Marine animals are divided into three groups: zooplankton, nekton, and benthos. Zooplankton are floating animals and are usually small; however, they can grow to fairly large size. The jellyfish and the Portuguese man-of-war are examples of larger types of zooplankton which are unable to move themselves effectively.

Nekton are the free swimmers and probably the largest part of familiar animals found in the ocean belong to this class. Common fishes, octopuses, whales, eels and squid are all examples of nekton.

The third type of sea animals spends their entire life on the bottom of the ocean. This group of marine animals is called benthos. Some of these creatures, such as lobsters and snails, may be able to move about on the bottom but their lifestyle is so closely linked with the ocean floor that they are unable to survive away from this environment.

【小题1】What does the text mainly introduce?

A．Marine plants and marine animals.	B．Two types of sea plants.
C．Three kinds of sea animals.	D．Small and big animals in the ocean.

【小题2】Why can’t we find the rooted plants in deep waters of the ocean?

A．Because there are too many rocks at the bottom of the ocean.

B．Because the rooted plants can’t stand the coldness of the ocean.

C．Because there is not enough sunlight for them in deep waters.

D．Because the rooted plants need more sunlight than plants which have no roots.

【小题3】One of the characteristics of zooplankton is that __________ .

A．they are small and never grow to large size

B．some of the zooplankton can’t swim quickly

C．they can swim freely in deep waters of the ocean

D．they need more sunlight than other animals in the ocean

【小题4】According to the last paragraph, we can conclude that __________ .

A．benthos live on the surface of the ocean water

B．some of the benthos can’t live without the ocean floor

C．benthos spend most of their time swimming in the ocean

D．benthos can move about in the middle of the sea water