One of the most popular activities enjoyed by Americans is spending time in forests and walking along paths through the country.This activity,called hiking,has led to the creation of paths throughout the United States.
One of the longest is the Appalachian National Scenic Trail.The trail is the first completed part of the National Trails System.The trails system was established by Congress and the president in 1968.The Appalachian Trail is more than 3,400 kilometers long.It starts in the northeastern state of Maine and ends in the southeastern state of Georgia.The trail goes through 14 states.They are Maine,New Hampshire,Vermont,Massachusetts,Connecticut,New York,New Jersey,Pennsylvania,Maryland,West Virginia,Virginia,Tennessee,North Carolina,and Georgia.
The path takes walkers through the Appalachian Mountains.They extend from the Canadian province of Quebec to the southern American state of Alabama.
The Appalachian Mountains are among the oldest on Earth.They first began forming about one thousand million years ago.During the millions of years since then,the mountains were changed and reformed by the forces of water and wind.Ice also changed the mountains,making many of them smaller and digging valleys and lakes among them.Many different kinds of trees grow along the trail.And many different kinds of animals live in the forests along the trail.
Lands along the trail are protected by the federal government and by state governments.Some parts are not protected by the government directly.Instead,they are protected by legal agreements with private owners willing to permit people to walk across their property.
Walkers on the Appalachian Trail pass through some of the great valley systems of the mountains.They can look down into these beautiful valleys and see farms and forests stretching across the land for many kilometers.Farmland in the valleys is rich and productive.And some of the great events in American history took place in the valleys.For example,one of the great battles of the American Civil War was fought in the Shenandoah Valley in Virginia.
1.The Appalachian Trail________.
A.is more than four thousand three hundred kilometers long
B.starts in the northern state of Maine
C.goes through more than fourteen states
D.ends in the southeastern state of Georgia
2. The Appalachian Mountains________.
A.are the first completed part of the National Trails System
B.began forming one million years ago
C.were changed by natural forces like water,wind and ice
D.were around by valleys and rivers and famous for its scenery
3. The lands along the trail________.
A.are protected entirely by either the federal government or state governments
B.are mainly protected by legal agreements with private owners
C.can be visited by travelers freely only under the permission of owners
D.are protected by both the federal government and state governments
4.What is mainly described in the last paragraph?
A.The Appalachian Mountains have some great valley systems.
B.Farms and grasslands stretch across the valleys for many kilometers.
C.One of the American independence battles was fought in the Shenandoah Valley.
D.Lakes in the Appalachian Mountains are one of the most beautiful sights.
Plastic is one of the most important technological discoveries of the 20th century.However,it may soon be replaced.The new development—liquid wood—can replace plastics in all branches of modern industries.
Plastic as a material enjoys the biggest demand in the modern world,but it does have a number of drawbacks.First and foremost,plastic isn’t recyclable.Secondly,it contains toxins (毒物) helping develop cancerous diseases.Finally,it’s made of oil and oil reserves aren’t endless.
The liquid wood technology is likely to replace plastic and provide mankind with new materials for many years ahead.Norbert Eisenfreich,a senior researcher at the Faunhofer Institute for Chemical Technology (ICT) in Germany,said that arboform,the new material,is made of lignin (木质素),which can be obtained from soft tissues of wood.Once mixed with several other materials,it turns into solid and nontoxic alternative for plastics.
ICT team leader Emilia Regina InoneKauffmann said the woodworking industry separates wood into three basic components,including lignin.Lignin isn’t used for the production of paper.Specialists of ICT mixed lignin with several natural materials and thus invented the material which could be melted and molded (铸型).
When solid,arboform looks like plastic and possesses the qualities of polished wood.It can be used for the production of any items.Arboform is already used for the production of car parts which require extra strength.In addition,liquid wood can be recycled repeatedly.The material preserved all of its qualities even if it’s reprocessed ten times.
However,the new invention doesn’t enjoy an extensive use due to the high content of sulphur (硫) in it.German researchers are sure to reduce the amount of sulphur by 90 percent very soon to make arboform usable for home needs.
1.According to the passage,plastic________.
A.plays a big role in the modern world
B.helps to protect our environment in some way
C.has been replaced by the newly discovered material
D.helps us to reduce the use of petrol
2.What’s the advantage of arboform over plastics?
A.It is easily made from natural oil.
B.It is more widely used in household.
C.It is recyclable and friendly to the environment.
D.It contains no poisonous materials.
3.It can be concluded that German researchers will focus their future work firstly on________.
A.the material’s extensive use
B.the content of sulphur in arboform
C.the production cost of arboform
D.the qualities of liquid wood
4.The main purpose of the passage is to________.
A.advertise the new material—arboform
B.introduce liquid wood which will replace plastic
C.advertise new products made of arboform
D.show readers how to produce arboform
His name is James,but people call him Rocky.The name fits.He’s big,over six feet tall,and he’s tough when he needs to be.James “Rocky” Robinson lives and works in New York City’s BedfordStuyvesant district,one of the poorest and most dangerous neighborhoods in the United States.Yet it is here in BedStuy that he is saving lives and reviving a community.
In 1966,when Rocky was twentysix years old,his sevenyearold niece was struck by a car on the street of BedStuy.Had someone at the scene known first aid or CPR,she might have lived.But by the time she reached a hospital,she was dead.
His niece’s unnecessary death was one reason why Rocky became a paramedic (护理人员).Working for the Emergency Medical Service of New York City,he realized that more than half the city’s emergency calls came from highcrime areas.According to Rocky,residents of crimeplagued minority neighborhoods like BedStuy sometimes had to wait as long as 26 minutes after calling 911 for an ambulance while calls in richer white communities were answered in_a_fraction_of_the_time.
Rocky decided to find out more about the problem.His research showed that the richer communities had organized their own ambulance corps (特殊部队) to improve city services because the city was overwhelmed with calls.“If that’s the key to success,”he told his friend and EMT (Emergency Medical Technician) colleague,Joe Perez,“we’ll start our own corps in BedStuy!”
In 1988,Rocky had no idea that he and Joe would be attempting to establish the first minorityrun ambulance service in the country,or just how creative he would have to be to overcome the difficulty.The pair’s first challenge was to find a location for the headquarters.They took over an abandoned building that was commonly used by drug dealers.Because there was no electricity or running water (except for the leaks in the roof),the two men worked during daylight hours.They used a twoway radio to receive emergency calls.
Although they could make do with their new headquarters,Rocky and Joe still lacked the most important component of an ambulance service:an ambulance.An old Chevrolet (雪佛兰) got them to the scenes of accidents,fires,shootings,and stabbings.But the car didn’t always start.At times,they were forced to strap (用带捆绑) their trauma kits and oxygen tanks to their backs and run on foot to the emergencies.Everyone laughed,except the victims who were still alive when Rocky and Joe arrived.
1.The author believes the name “Rocky” fits James because________.
A.he is a tall and tough man
B.he is tall and does something big
C.he is living in a tough community
D.he leads a tough community
2.James’ sevenyearold niece would have been saved if________.
A.she had been sent to a better hospital
B.she had got first aid and arrived in hospital earlier
C.James had been at the spot
D.emergency calls had been available in the area
3.The underlined phrase in Paragraph 3 means________.
A.in a short time
B.over a long time
C.in the near future
D.from time to time
4.We can infer from Paragraph 4 that________.
A.ambulance corps were only allowed in rich white communities
B.James found white communities made more emergency calls
C.city services were not enough to meet people’s need
D.it was easy to establish the minorityrun ambulance service
Five cloned pigs,whose organs are much less likely to be rejected(排斥) by a patient,have been born in the U.S.
More than 62,000 people in the U.S. alone are waiting to ____ donated hearts,lungs and so on.The number of human donors falls far short of ____.Pig organs are of a(n) ____ size to human organs,and some scientists hope they might be used to help meet the ____.But previous attempts to transplant pig tissue into humans have ____.
The five pigs ____ a gene that adds a sugar to the surface of pig cells.The sugar would ____ immune(免疫的) rejection of the tissue.“This advance provides a neartime ____ for overcoming the problem that there is not enough human organs for transplants,”says an expert.“This is the ____ gene for overcoming the ____ stage of rejection.”
____,scientists warn that much more work is necessary ____ organs from copies of the pigs could be transplanted into humans.Human genes will need to be added,to ____ rejection of the organ in the long term.There are also ____ that pig viruses could infect patients.
Cloning techniques were ____ to the production of the pigs.Genes can only be knocked out(去除) in a single cell.Cloning of these single cells then allowed the ____ of a whole animal in which the gene was knocked out in every cell.But the PPL researchers have ____ in knocking out only one copy of the gene.The team will now attempt to knock out both copies of the gene.
The team will also ____ tests to investigate whether a virus from the pigs could infect human cells.“Although a lot of the work is very ____,we’re still very far off being able to grow an organ,” says Julia,who is working on this project and quite ____ to creating similar knockout pigs with researchers at the University of Missouri.
1.A.exchange B.check
C.possess D.receive
2.A.discussion B.demand
C.doubt D.distance
3.A.beneficial B.identical
C.similar D.certain
4.A.shortage B.condition
C.satisfaction D.argument
5.A.continued B.failed
C.finished D.paused
6.A.lack B.include
C.make D.change
7.A.leave B.cause
C.block D.destroy
8.A.supply B.ambition
C.contribution D.solution
9.A.only B.rare
C.key D.safe
10.A.last B.whole
C.next D.early
11.A.However B.Therefore
C.Besides D.Finally
12.A.because B.before
C.if D.after
13.A.prevent B.ignore
C.judge D.weaken
14.A.regrets B.emotions
C.concerns D.interests
15.A.simple B.vital
C.unusual D.basic
16.A.collection B.application
C.reception D.creation
17.A.delighted B.succeeded
C.joined D.believed
18.A.conduct B.plan
C.design D.study
19.A.perfect B.strange
C.exciting D.disappointing
20.A.opposed B.used
C.devoted D.suited
________,John returned to school from his hometown.
A.The summer vacation being over
B.The summer vacation is over
C.Because the summer vacation over
D.After the summer vacation being over
—We didn’t find the Blacks ________ the lecture.
—No one had told them about ________ a lecture the following day.
A.attending;there being B.to attend;there to be
C.attended;there be D.attend;there was