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Transport and Trade
1.Transport is one of the aids to trade.By moving goods from places where they are plentiful to places where they are scarce,transport adds to their value.The more easily goods can be brought over the distance that separates producer and consumer,the better for trade.When there were no railways,no good roads,no canals,and only small sailing ships,trade was on a small scale.
2.The great advances made in transport during the last two hundred years were accompanied by a big increase in trade.Bigger and faster ships enabled a trade in meat to develop between Britain and New Zealand,for instance.Quicker transport makes possible mass-production and big business, drawing supplies from,and selling goods to,all parts of the globe.Big factories could not exist with-out transport to carry the large number of workers they need to and from their homes.Big city stores could not have developed unless customers could travel easily from the suburbs and goods delivered to their homes.Big cities could not survive unless food could be brought from a distance.
3.Transport also prevents waste.Much of the fish landed at the ports would be wasted if it could not be taken quickly to inland towns.Transport has given us a much greater variety of foods and goods since we no longer have to live on what is produced locally.Foods which at one time could be obtained only during a part of the year can now, be obtained all through the year. Transport has raised the standard of living.
4.By moving fuel,raw materials,and even power,as,for example,through electric cables, transport has led to the establishment of industries and trade in areas where they would have been impossible before.Districts and countries can concentrate on making things which they can do better and more cheaply than others and can then exchange them with one another. The cheaper and quicker transport becomes,the longer the distance over which goods can profitably be carried.Countries with poor transport have a lower standard of living.
5.Commerce requires not only the moving of goods and people but also the carrying of messages and information. Means of communication,like telephones,cables and radio,send information about prices,supplies,and changing conditions in different parts of the world.In this way,advanced communication systems also help to develop trade.
The development of modern means of transport_______.
A:to send goods to various parts of the world
B:at any time during the year
C:has greatly promoted trade
D:is it possible to produce on a large scale
E:the transport of goods
F: it is possible to produce on a large scale

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第二篇
Ants Have Big Impact on Environment as "Ecosystem Engineers"
Research by the University of Exeter has revealed that ants have a big impact on their local environment
as a result of their activity as"ecosystem engineers"and predators.The study,published in the Journal of
Animal Ecology,found that ants have two distinct effects on their local environment.
Firstly,through moving the soil by nest building activity and by collecting food they affect the level of
nutrients in the soil.This can indirectly impact the local populations of many animal groups,from decomposers
to species much higher up the food chain.
Secondly,they prey on a wide range of other animals,including larger prey which can be attacked by
vast numbers of ant workers.
Dirk Sanders,an author of the study from the university's Centre for Ecology and Conservation,said,
"Ants are very effective predators which thrive in huge numbers.They're also very territorial and very
aggressive,defending their resources and territory against other predators.All of this means they have a strong
influence on their surrounding area."
"In this research,we studied for the first time how big this impact is and the subtleties of it.What we
found is that despite being predators,their presence can also lead to an increase in density and diversity of
other animal groups.They genuinely play a key role in the local environment,having a big influence on the
grassland food web,"Sanders said.
The study,carried out in Germany,studied the impact of the presence of different combinations and
densities of black garden ants and common red ants,both of which can be found across Europe,including the
UK. It found that a low density of ants in an area increased the diversity and density of other animals in the
local area,particularly the density of herbivores and decomposers.At higher densities ants had no or the
opposite effect,the predation counteracting the positive influence.
Dr Frank van Veen,another author on the study,said:"What we find is that the impact of ants on soil
nutrient levels has a positive effect on animal groups at low levels,but as the number of ants increases,their
predatory impacts have the bigger effect一thereby counteracting the positive influence via ecosystem engineering."
Ants are important components of the ecosystem not only because they constitute a great part of the
animal biomass but also because they act as ecosystem engineers.Ant biodiversity is incredibly high,and
these organisms are highly responsive to human impact,which obviously reduces its richness.However,it is
not clear how such disturbance damages the maintenance of ant services to the ecosystem.Ants are important
in below ground processes through the alteration of the physical and chemical environment and through their
effects on plants,microorganisms,and other soil organisms.
What does Paragraph 6 tell us?
A:Ants bring about a negative influence to an area when their population is small.
B:Ants bring about a positive influence to an area when their population is small.
C:Ants' predation counteracts the positive influence they may have on an area.
D:At higher density,ants produce a positive influence on an area.

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Avalanche and Its Safety
An avalanche is a sudden and rapid flow of snow,often mixed with air and water,down a mountainside .Avalanches are______(51)the biggest dangers in the mountains for both life and property.
All avalanches are caused by an over-burden of material,typically snowpack,that is too massive and unstable for the slope______(52)supports it. Determining the critical load,the amount of over-burden which is______(53)to cause an avalanche，______（54)a complex task involving the evaluation of a number of factors.
Terrain slopes flatter than 25 degrees or steeper than 60 degrees typically have a low ______(55)of avalanche .Snow does not______(56)significantly on steep slopes;also, snow does not______(57)easily on flat slopes.Human-triggered avalanches have the greatest incidence when the snow's angle of rest is______(58)35 and 45 degrees;the critical angle, the angle at which the human incidence of avalanches is greatest,is 38 degrees.The rule of thumb is:A slope that is______(59)enough to hold snow but steep enough to ski has the potential to generate an avalanche,regardless of the angle.Additionally,avalanche risk increases with ______(60);that is,the more a slope is disturbed by skiers,the more likely it is that an avalanche will occur.
Due to the complexity of the subject,winter travelling in the backcountry is never 100% safe .Good avalanche safety is a continuous______(61),including route selection and examination of the snowpack,weather______(62),and human factors.Several well-known good habits can also______(63)the risk .If local authorities issue avalanche risk reports,they should be considered and all warnings should be paid______(64)to.
Never follow in the tracks of others without your own evaluations;snow conditions are almost certain to have changed since they were made .Observe the terrain and note obvious avalanche paths where plants are ______(65)or damaged .Avoid travelling below others who might trigger an avalanche.
51._________
A: among
B: on
C: at
D: with

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Most people findrejectionhard to accept.
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Robots May Allow Surgery in Space
Small robots designed by University of Nebraska researchers may allow doctors on
Earth to help perlorm surgery on patients in space.
The tiny,wheeled robots,_________(1)are about 3 inches tall and as wide as a
lipstick case, can be slipped into small incisions（切口）and computer-controlled by
surgeons in different locations.Some robots are equipped_________(2)cameras and
lights and can send images back to surgeons and others have surgical tools attached that
can be_________(3)remotely.
"We think this is going to_________(4)open surgery,"Dr. Dmitry Oleynikov said
at a news conference.Oleynikov is a_________(5)in computer-assisted surgery at
the University of Nebraska Medical Center in Omaha.
Officials hope that NASAwill teach_________(6)to use the robots soon enough so
that surgeries could one day be performed in space.
On earth,the surgeons could control the robots themselves_________(7)other
locations.For example,the robots could enable surgeons in other places to_________
(8)on injured soldiers on the front line.Researchers plan to seek federal regulatory
_________(9)early next year.Tests on animals have been successful,and tests on
humans in England will begin very soon.
The camera-carrying robots can provide_________(10)of affected areas and the
ones with surgical tools will be able to maneuver（操控）inside the body in ways surgeons'
hands can't.The views from the camera-carrying robots are_________(11)than the
naked eye,because they_________(12)back color images that are magnified（放大）.
Because several robots can be inserted through one incision,they could reduce the amount
and_________(13)of cuts needed for surgery,which would decrease recovery time.
This is particularly_________( 14) to those patients who have been debilitated（使虚弱）
by long illness.
Eventually,Oleynikov said,the tiny robots may enable surgeons to work without ever
_________(15)their hands in patients' bodies."That's the goal,"Oleynikov said."It's
getting easier and easier.We can do even more with these devices."
_________(6)
A:astronauts
B:nurses
C:teachers
D:trainers

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The contempt he felt for his fellow students was obvious.
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B: need
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