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A. is covered with sad and grass
B. has a long history
C. occupies much of South Nigeria
D. belongs to Sudan
答案
更多“The Sahel zone is an area which”相关的问题
第1题
Desertification， drought， and despair－that＇s what global warming has in store for much of Africa. Or so we hear.
Emerging evidence is painting a very different scenario， one in which rising temperatures could benefit millions of Africans in the driest parts of the continent. Scientists are now seeing signals that the Sahara desert and surrounding regions are greening due to increasing rainfall. If sustained， these rains could revitaliｚe drought－ravaged regions， reclaiming them for farming communities. This desert－shrinking trend is supported by climate models， which predict a return to conditions that turned the Sahara into a lush savanna some 12，000 years ago.
The green shoots of recovery are showing up on satellite images of regions including the Sahel， a semi－desert ｚone bordering the Sahara to the south that stretches some 2，400 miles.
Images taken between 1982 and 2002 revealed extensive regreening throughout the Sahel， according to a new study in the journal Biogeosciences. The study suggests huge increases in vegetation in areas including central Chad and western Sudan. The transition may be occurring because hotter air has more capacity to hold moisture， which in turn creates more rain， said Martin Claussen of the Max Ｐlanck Institute for Meteorology in Hamburg， Ｇermany， who was not involved in the new study. ＂The water－holding capacity of the air is the main driving force，＂ Claussen said.
While satellite images can＇t distinguish temporary plants like grasses that come and go with the rains， ground surveys suggest recent vegetation change is firmly rooted. In the eastern Sahara area of southwestern Egypt and northern Sudan， new trees—such as acacias—are flourishing， according to Stefan Ｋr？pelin， a climate scientist at the University of Cologne＇s Africa Ｒesearch Unit in Ｇermany.
＂Before， there was not a single scorpion， not a single blade of grass，＂ saidＫr？pelin， who has studied the region for two decades.＂Now you have people graｚing their camels in areas which may not have been used for hundreds or even thousands of years. Ｙou see birds， ostriches， gaｚelles coming back， even sorts of amphibians coming back，＂ he said.＂The trend has continued for more than 20 years. It is indisputable.＂
An explosion in plant growth has been predicted by some climate models.For instance， in 2005 a team led by Ｒeindert Haarsma of the Ｒoyal Netherlands Meteorological Institute in De Bilt， the Netherlands， forecast significantly more future rainfall in the Sahel.The study in Ｇeophysical Ｒesearch Letters predicted that rainfall in the Ｊuly to September wet season would rise by up to two millimeters a day by 2080.
Satellite data shows ＂that indeed during the last decade， the Sahel is becoming more green，＂ Haarsma said.Even so， climate scientists don＇t agree on how future climate change will affect the Sahel： Some studies simulate a decrease in rainfall.＂This issue is still rather uncertain，＂ Haarsma said.
Max Ｐlanck＇s Claussen said North Africa is the area of greatest disagreement among climate change modelers.Forecasting how global warming will affect the region is complicated by its vast siｚe and the unpredictable influence of high－altitude winds that disperse monsoon rains， Claussen added.＂Half the models follow a wetter trend， and half a drier trend.＂
86. According to the first paragraph， global warming is supposed to have the following impacts on Africa EＸCEＰT
A.water deficiency
B.distress
C. desertifications
D. more grasses and lakes
第2题
Questions 26 to 30 are based on the following passage:
Over vast areas of every continent,the rainfall and vegetation necessary for life are disappearing.Already more than 40 percent of the earth's land is desert or desertlike.About 628 million people—one out of seven—live in these dry regions.In the past,they have managed to survive,but with difficulty.[ZZ(Z]Now largely through problems caused by modern life,their existence is threatened by the slow,steady spread of the earth's deserts. Scientists still do not understand all the complex problems of the desert,but there have been many ideas for saving the land.Sandi Arabia has planted 10 million trees to help keep the sand from taking over fertile areas.The Israelis are aga in using some of the water collection systems left by the ancient people in the Negev desert.They plan to water their orchards with the extra water.Some Sahel farmers still raise cattle on their poor farm land,but before the cattle are sold, they are taken to greener lands in the south to get fat.
26. What is the article mainly concerned？
A.The problem of spreading desert.
B.The rainfall and vegetation in desert areas.
C.The water collection systems.
D.The difference between modern life and ancient life.
27. “one out of seven” refers to____.
A.more than a third of the lands' earth
B.the percentage of the earth's land that is desert-like
C.the number of people who live in dry regions
D.a day of a week
28. In paragraph 2,“they are taken to the greener lands in the south.”They refers to____.
A.the Sahel farm land
B.the farmers
C.the cattles
D.the trees
29. How many ideas for saving the land are described？
A.Five. B.Two. C.Four. D.Three.
30. Which of the following statements is true, according to the passage？
A.The earth's desert are slowly spreading.
B.One out of 10 people lives in dry regions.
C.Their life in the desert is threatened now by traditional problems.
D.New water wells can solve the problem in Africa's desert.
第3题
A.Focus zone
B.Computation zone
C.Printing zone
D.Filtering zone
第5题
A.firewall-cmd --zone=external --add-port=3128/tcp
B.firewall-cmd --zone=external --add-port=tcp3128
C.firewall-cmd --zone=internal --add-port=3128/tcp
D.firewall-cmd --zone=internal --add-port= tcp3128
第6题
A．highland zone
B．lowland zone
C．east zone
D．west zone
第8题
Which of the followings is NOT the natural zone in Scotland？
A．Highlands.
B．Flatlands.
C．Uplands.
D．Lowlands.
第10题
