building can house a vertical farm.Since the garden is built upwards,rather than outwards,it
requires much less space than a conventional(传统的) farm.
The world is quickly running out of room for conventional farming.Vertical farms could be
a key to this situation.An 18story vertical farm could feed as many as 50,000 people,all in an
area which is the size of the average city block.Vertical farms in the city could cut down on
transportation costs as well.Think about the amount of fuel it takes to transport food from
farmland to city.The resources saved would be surprising. Besides saving travel time,food
would be delivered in fresher condition and with less damage.
There is a growing concern about the use of pesticides in agriculture today.But the vertical
farm would be a greenhouse type environment, avoiding the need for a large number of
pesticides.Vertical farms can be built in a contained space,therefore they are an excellent
solution for living well in an environment far different from our own.Hydroponics(水耕法)
could be a big part of vertical gardening.This would reduce the amount of soil needed to grow
food.Of course,not all food does well with this type of planting,but there are many crops
that actually seem to do better.
In some climates,a lack of sunlight creates a short growing season. The solar power option
may not work as well here.The addition of grow lights would make it possible to grow crops
in vertical gardens in these areas.In other words,we could grow crops in areas where we never
could before.
Vertical farms may just be a concept for now,but they are a concept that will solve many
of our problems in the future.
B.is only an environmental friendly farm
C.is planted on levels upwards
D.is dependent on solar power
B.the future of a vertical farm
C.the cost of a vertical farm
D.the benefit of a vertical farm
B.reduce the harmful effect of pesticides
C.depend far less on sunlight
D.greatly increase the use of soil
B.need less room than conventional farms
C.only use hydroponics to grow food
D.may increase the transportation costs
B.Vertical farms and green skyscrapers
C.Ways to deal with future problems
D.Advantages of vertical farms
on February 23. It was the third shark attack along the coast of Australia"s largest city in a month.
The 15yearold boy and his father were in the water off Avalon, on Sydney"s northern beaches,
around dawn when he was attacked. The city"s beaches are packed with locals and tourists during the
summer months.
"The father heard a scream and turned to see his son thrashing(激烈扭动)about in the water, "police
said. "Fortunately, the shark swam away and the boy was helped to the shore by his father. "
Lifesaving Club spokesman Nick Miller said, "It got him around the top of his left leg and the father
came and dragged him out of water. "He said the boy was bleeding heavily when he was brought to the
shore. "There was a lot of pain, as you can imagine. "The teenager was airlifted to hospital for treatment
for leg injuries.
Police said the bites "cut through to the bone", but the boy did not appear to have sustained any
fractures (骨折). He was in a stable condition now.
Several beaches were closed after the attack. Water police and lifeguards were searching for the
shark, while police hoped to identify its species by the shape of the bite marks. But they said it was too
early to say what type of shark attacked the boy. "I don"t even know if he saw it, "Miller said.
Many shark species live in the waters off Sydney"s beaches, but attacks on humans are still relatively
rare. However, there were two attacks on successive days earlier this month, one on a navy diver in
Sydney harbor, not far from the famous Opera House, and the other on a surfer at the city"s
worldfamous Bondi beach.
Fishermen say shark numbers are on the rise. There is a ban on commercial fishing in the harbor,
which has increased fish stocks. Marine experts also claim environmental protection has created a
cleaner environment, attracting sharks closer to the shore as they chase fish. Many shark species,
including the Great White-the maneaters made famous in Steven Spielberg"s Jaws-are protected in
Australian waters.
B. sharks attacked humans three times in one month
C. a boy was attacked by a shark at a Sydney beach
D. shark numbers are increasing in the waters off Sydney"s beaches
B. dragged
C. bit
D. packed
B. Sydney harbor is not far from the famous Opera House.
C. There are many locals and tourists on its coast all the year round.
D. There are few shark species in the waters off Sydney"s beaches.
B. he was very nervous when he was sent to hospital
C. he may be in danger of losing his leg
D. he was injured in the right leg
B. a ban on commercial fishing has increased fish numbers
C. many shark species are protected in Australian waters
D. the film Jaws has made the Great White famous
We"ve used the wind as an energy source for a long time.The Babylonians and Chinese were using wind power to pump water for irrigating crops 4000 years ago, and sailing boats were around long before
that.Wind power was used in the Middle Ages, in Europe, to grind (磨碎) corn, which is where the term "windmill" comes from.
We can use the energy in the wind by building a tall tower, with a large propellor on the top.The wind
blows the propellor round, which turns a generator to produce electricity.
We tend to build many of these towers together, to make a "wind farm" and produce more electricity.The more towers, the more wind, and the larger the propellors, the more electricity we can make.It"s only worth building wind farms in places that have strong, steady winds, although boats and caravans (大篷车) increasingly have small wind generators to help keep their batteries charged.
The best places for wind farms are in coastal areas, at the tops of rounded hills, open plains and gaps in mountains-places where the wind is strong and reliable.Some are offshore.To be worthwhile, you need
an average wind speed of around 25 km/h.Most wind farms in the UK are in Cornwall or Wales.Isolated places such as farms may have their own wind generators.In California, several "wind farms" supply
electricity to homes around Los Angeles.
The propellors are large, to obtain energy from the largest possible volume of air.The blades can be
angled to cope with varying wind speeds.Some designs use vertical turbines (垂直涡轮机), which don"t
need to be turned to face the wind.The towers are tall, to get the propellors as high as possible, up to
where the wind is stronger.This means that the land beneath can still be used for farming.
B. the source of wind power
C. the nations using wind power
D. the history of using wind power
B. The tall tower helps turn the energy in the air into electricity.
C. Warm air rises and makes the propellor move round.
D. The propellor blown round by wind turns the generator to produce electricity.
B. isolated farms don"t have enough electricity
C. there are less human activities
D. the wind is strong and reliable
B. wind farms need no fuel because wind is free
C. the blades can be angled to turn to face the wind wherever it comes from
D. the higher and larger the towers are, the stronger the wind is
B. ABC of the using of wind energy
C. How to make best use of wind
D. Wind energy is the best energy
traditional public schools.In the United States the rules for charter schools differ from state
to state.But in general these schools have greater freedom to decide what to teach and how
to teach it.
The "charter" is a performance contract.It establishes the goals of the school and other
details like how student performance will be measured.Fortyseven million students attend
traditional public schools.But more than a million students attend charter schools.
And now a group of charter schools have formed the Green Charter Schools Network.
The idea is to have environmentally friendly school buildings but to also go further than that.
The schools teach students to become involved in community issues that affect them and
the environment.For example,young children grow crops in a school garden and learn
about healthy eating.Older students help recycle waste from the cafeteria.And local schools
share what they grow in community gardens with people in need.
Jim McGrath is president of the Green Charter Schools Network.He says there are
about 200 "green" charter schools across the United States.He says the plan is to also
include traditional public schools as well as private schools.
Jim McGrath:"The most important thing is that every one of us-every child,every
adult-has a responsibility that their action,every action we make has an effect on the earth
that we live in.And that our natural resources are not unlimited.And that if we want a
positive earth for future generations,we all need to make commitments to be agents of
change so that we don"t destroy our natural resources."
T he Green Charter Schools Network holds its first national conference this October
in Minnesota.It will include companies and organizations like Waste Management and the
United States Green Building Council.We sincerely hope that their goal is to expand the
movement across the country.
B.they still use the traditional rules
C.they have more freedom in management
D.they attract more students than others
B.paint the school buildings in the color of green
C.measure the students with the same standards
D.get students involved in environment friendly activities
B.It holds its first national conference in Minnesota
C.It will benefit both the schools and the communities
D.It promotes different schools to share their achievements
B.natural resources are abundant for people to use
C.students should be taught to be responsible for the world
D.everyone should make efforts to change the positive nature
B.To encourage the students to adopt healthy eating.
C.To inspire people to recycle waste from the cafeteria.
D.To arouse the schools to take action to protect the earth.
A new study in West Africa shows how farm irrigation systems powered by the sun can
produce more food and money for villagers.The study in Benin found that solarpowered pumps
are effective in supplying water,especially during the long dry season.
SubSaharan Africa is the part of the world with the least food security.The United Nations
Food and Agriculture Organization estimates that more than one billion of the world"s people
faced hunger last year.Around 265 million of them live south of the Sahara Desert.Lack of
rainfall is one of their main causes of food shortages.
Jennifer Burney from Stanford University in California led the study.The research team
helped build three solarpowered drip irrigation (滴灌) systems in northern Benin.Between
30 and 35 women used each system to pump water from the ground or a stream.Each
woman was responsible for farming her own 120 square meters of land.They also farmed
other land collectively.
The solarpowered irrigation systems produced an average of nearly two tons of vegetables
per month.During the first year,the women kept a monthly average of almost nine kilograms
of vegetables for home use.They sold the surplus produce at local markets.The earnings
greatly increased their ability to buy food during the dry season which can last six to nine
months.People in the two villages with the systems were able to eat three to five more
servings of vegetables per day.But making the surplus available at markets also had a wider
effect.
The study compared the villages with two others where women farmed with traditional
methods like carrying water in buckets.The amount of vegetables eaten in those villages also
increased,though not as much.The researchers note that only four percent of the cropland in
SubSaharan Africa is irrigated.Using solar power to pump water has higher costs at first.But
the study says it can be more economical in the long term than using fuels like gasoline,diesel
or kerosene.And solar power is environmentally friendly.
B.limitation of farmland
C.a small crop variety
D.little sunlight
B.the farmers irrigate the land together
C.all farmers use irrigation systems in northern Benin
D.the solarpowered systems take up more manpower
B.unnecessary
C.extra
D.abandoned
B.solar power helps to protect environment
C.solar power helps farmers increase earnings
D.solar energy can be more economical in the long run
B.Irrigation by carrying water in buckets
C.Solarpowered pumps aid African farmers
D.Vegetable supply increased in African villages
Back to the Future was boffo at the box office."Born in the USA" was climbing the charts.Philanthropy
(慈善业) and pop culture combined with LiveAid and "We Are the World. " And " .com ", which few
people outside of the military or universities knew,came into this world.
Looking back,few could have predicted ".com" would become one of the biggest cultural touchstones
of the century.In March 1985,the Information Sciences Institute at the University of Southern California
assigned the first.com domain address to symbolics.com.That seemingly nominal (象征性的) event set into
motion forces that would change our world forever.
.com wasn"t the birth of the Internet,but it was the budding computer network"s comingout party.It made
it pretty and inviting.It did away with the need to have complex "maps" that were the equivalent of writing a
phone number on your hand,and opened it up for a mainstream audience.
After 1985,all it takes is a simple.com name to get into business.".com" became part of our daily lexicon
and drove its own economic boom and depression. It helped create a whole new family of industries,
facilitated global commerce and connected people around the world in ways never before possible.
It"s now 2010.Barack Obama is president,thanks in part to his smart use of the Internet.There is no
USSR.A computergenerated Avatar has set new box office records."TiK ToK" tops the charts.We"re
sending robots to find water on Mars.And that onceobscure computer communications system is one of
our civilization"s most prominent features.
B.the development of entertainment
C.the 25th anniversary of.com
D.the anniversary of the internet
B.Changeable.
C.Tough.
D.Novel.
B.It combined politics,entertainment and space science.
C.It made the Internet accessible to ordinary people.
D.It helped produce more domain addresses.
B.complex
C.expensive
D.popular
B.provide details
C.list arguments
D.stimulate readers" interest
- 1已知A(1,2),B(3,5),=(4,7),则在方向上的投影为( )。
- 2将弯曲的河道改直,用了我们数学中的( )。
- 3如图,四棱锥P-ABCD中,底面ABCD为正方形,DA⊥面ABP,AB=1,PA=2,∠PAB=600,E为PA的中点,
- 4--- I’ll have an interview for the job at that school, and n
- 5“前怕狼,后怕虎”所导致的挫折是——造成的。( )A.自然因素B.社会因素C.客观因素D.主观因素
- 6如图,点A在反比例函数y= (x>0)图象上,且OA=4,过A作AC⊥x轴,垂足为C,OA的垂直平分线交OC于B.
- 7下列各组中的性质比较,正确的是 ( )①酸性:HClO4>HBrO4>HIO4 ②碱
- 8依次填入下列各句横线处的词语,最恰当的一项是 ( )①温家宝总理在政府工作报告中,就
- 91953年12月,我国进行首次普选,采用直接选举与间接选举相结合的选举方式。其中,乡镇人大代表实行直接选举,各级人大代表
- 10一工人在房顶上敲钉子,每秒敲4下.当工人开始敲钉,一个观察者恰巧在看到他把锤举到最高处时,听见敲打的声音,如果空气中的声
- 1依次填入下列各句横线处的词语,恰当的一组是①30年后再回母校,他__的记忆被激活了,许多的人和事又清晰的浮现在脑海中。②
- 2 对“幸福”的理解因人而异。请仿照示例,将下面作品中人物的话补写完整,表达人物对“幸福”的理解。要求:①符合人物的思想
- 3_____ she had not spelt the word wrong, Cathy would have got
- 4—What are these? —______ are buses.[ ]A. They B.
- 5以下是一组各个时期留下的宣传标语,按先后出现的顺序排列正确的是①②③④
- 62003年10月15日,我国用“长征”二号F捆绑式火箭将“神舟五号”载人飞船成功送入太空.火箭用联氢(N2H4)作燃料,
- 7已知,则= .
- 8如图所示,电源电压为6V且保持不变。当滑动变阻器的滑片P移动到最右端B时,闭合开关,电流表示数为0.2A,电压表示数为4
- 9对人类社会史前史的研究,始于19世纪中后期。下列著作中系统探讨人类社会史前史的是[ ]A、《物种起源》B、《国家
- 10下列词语中加粗字注音全部正确的一项是 [ ]A.粗鄙(bǐ)烂漫(màn)犀利(xì)绽开(zhàn)B.绯红(