What comes to mind when you think of a lake? You probably imagine a pretty scene with blue water，birds，and fish．For the people in the northwestern Cameroon，however, the image is very different. For them，lakes may mean terrible disasters. In 1984，poisonous gases exploded out of Lake Monoun and came down into the nearby villages，killing thirty—seven people．Two years later,Lake Nyos erupted A cloud of gases rolled down the hills and into the valleys and killed 1,700 people．
Lake Nyos and Lake Monoun are crater(火山口)lakes They were formed when water collected in the craters of old volcanoes The volcanoes under Lake Nyos and Lake Monoun are not active anymore. However, poisonous gases from the center of the earth continue to flow up through cracks in the bottom of the lake. This is normal in a crater lake. In most crater lakes，these gases are released often because the water?turns over?regularly．That is，the water from the bottom of the lake rises and mixes with the water at the top，allowing the gases to escape slowly．
However，in Lakes Nyos and Monoun，there is no regular turning over．No one knows the reason for this fact，but as a result，these lakes have more gases tapped at the bottom than other crater lakes. In fact，scientists who have studied Lakes Nyos and Monoun have found 16,000 times more gases．When a strong wind，cool weather a storm，or a landslide(滑坡)causes the water to turn over suddenly，the gases escape in a violent explosion．
In the past，no one knew when the gases might explode，so there was no way for the villagers to escape disaster. Now scientists from the United States，France，and Cameroon have found a way to reduce the gas pressure at the bottom of Lake Nyos．They stood a 672-foot plastic pipe in the middle of the lake，with one end of the pipe near the bottom and the other end in the air．Near the top of the pipe，the team put several holes that could be opened or closed by a computer．Now，when the gas pressure gets too high，the holes are opened and some of the gas-filled water shoots up through the pipe into the air like a fountain．With less pressure，a disastrous explosion is much less likely．However, the scientists are not sure that one pipe will be enough to prevent
explosions．They hope to put in others soon and they plan to install a similar pipe and a computer system at Lake Monoun as well．
To protect people nearby until all of the pipes are in place．the scientists have installed early warning systems at both lakes. If the gas pressure rises to a dangerous level，computers will set off loud sirens(警报)and bright lights to warn the people in the villages．That way, they will have time to escape from the dangerous gases．
41 What will happen when Lake Nyos and Lake Monoun explode? A Water will flow down the hills
B Poisonous gases will be released suddenly． C A strong wind will rise from the lakes
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D The volcanoes will come to life．
42 Which of the following statements about Lake Nyos and Lake Monoun is true? A They were formed in 1984．
B They are at the top of two active volcanoes． C They are not like most other crater lakes． D Water in them turns over regularly．
43 Lake Nyos and Lake Monoun explode because A the gases rise to the top and mix with air． B people from the villages turn over the water． C scientists have put in a computer system．
D they have more gases trapped at the bottom than other crater lakes 44 A team of scientists has
A erected a pressure-releasing pipe in the lake B identified the gases at the bottom of the lake C built a beautiful fountain near the lakes D removed all dangerous gases from the lakes 45 What do we learn from the last paragraph?
A Scientists are planning to install pipes in all crater lakes． B Scientists still do not know how to prevent gas explosions C Explosion disasters could be avoided in the future D Warning systems have been set up in the villages nearby． 参考答案：
41．B 42．C 43．D 44．A 45．C
第5部分：补全短文 (第46～50题，每题2分，共1 0分)
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阅读下面的短文，文章中有5处空白，文章后面有6组文字，请根据文章的内容选择5 组文字，将其分别放回文章原有位置，以恢复文章原貌。请将答案涂在答题卡相应的位置 上。
Every Dog Has Its Say
Kimiko Fukuda，a Japanese girl，always wondered what her dog was trying to say.
Whenever she put on makeup，it would pull at her sleeve．_____(46)When the dog barks，she glances at a small electronic gadget (装置)．The following“human”translation appears on its screen：“Please take me with you．”“I realized that?s how he was feeling．”said Fukuda． The gadget is called Bowlingual，and it translates dog barks into feelings．People laughed when the Japanese toymaker Takara Company made the world?s first dog-human translation machine in 2002．But 300，000 Japanese dog owners bought it．______(47) “Nobody else had thought about it，”said Masahiko Kajita，who works for Takara“We spend so much time training dogs to understand our orders；what would it be like if we could understand dogs?”
Bowlingual has two parts．____(48)The translation is done in the gadget using a database(资料库)containing every kind of bark．
Based on animal behaviour research，these noises are divided into six categories：happiness，Sadness, frustration，anger，declaration and desire．_____(49)In this way，the database scientifically matches a bark to an emotion，which is then translated into one of 200 phrases． When a visitor went to Fukuda?s house recently，the dog barked a loud“bow wow”．This translated as“Don?t come this way”_____(50)
The product will be available in US pet stores this summer for about US$120 It can store up to 100 barks，even recording the dog?s emotions when the owner is away．
A A wireless microphone is attached to the dog?s collar,which sends information to the gadget held by the owner．
B Nobody really knows how a dog feels
C It was followed by“I?m stronger than you”as the dog growled(嗥叫)and sniffed(嗅)at the visitor
D More customers are expected when the English version is launched this summer E Now，the Japanese girl thinks she knows
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F Each one of these emotions is then linked to a phrase like“Let?s play”，“Look at me”，or“Spend more time with me”． 参考答案：
46．E 47．D 48．A 49．F 50．C
第6部分：完形填空 (第5l～65题，每题1分，共1 5分)
阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从 4个选项中选择1个最佳答案，涂在答题卡相应的位置上。 Earth?s Inner Core
Scientists have long struggled to understand what lies at the planet?s center, Direct observation of its center is impossible，so researchers must_____(51)to other evidence．
In 1889，a German scientist detected a severe earthquake in Japan．Geophysicists concluded that shock waves_____(52)jolts(晃动)from one side of Earth through the center to the other side．Then in 1936，Danish geophysicist Inge Lehmann studied the waves______(53) to determine that within Earth?s core of molten(熔化了的)iron lies a solid inner core-but_____ (54)that core was made of eluded(难倒)her．Other geophysicists quickly determined that Lehmann?s inner core was
composed mostly_____(55)iron. Since then， Lehmann?s discovery has_____(56)conventional Earth science． But now scientists are challenging traditional theory with new and radical _____(57)
For example，Earth?s center could actually contain an“inner core within the inner core，claim Ishii and colleague Adam Dziewonski．
Analyzing hundreds of thousands of earthquake wave _____(58),they maintain that the inner core has at its heart a tiny, even more solid sphere(球体) . This sphere??may be the oldest fossil____(59)from the formation of Earth，”says Dziewonski．
Dziewonski and Ishii speculate that shortly_____(60) Earth formed around 4.8billion years ago，a giant asteroid(小行星)smashed into the young planet and nearly melted it. But Earth?s center didn?t quite melt；it______(61)mass as the planet cooled. The core within a core may be the kernel(核心)that endured．“Its presence could change our basic ideas about the_____ (62)of the planet，”Dziewonski says idea is tame(温和的)compared to the_____(63)theories of independent geophysicist J．Marvin Herndon．Earth?s inner core is made not of iron，he claims
but a_____(64)of nickel and silicon Hemdon has a truly revolutionary notion：Within the nickel silicide(硅化物)inner core is also an“inner”inner core—an 8 km—wide ball of the element uranium．Uranium is radioactive．Hemdon thinks the uranium releases heat energy as its
atoms_____(65)fission-split and crash into another in a chain reaction. In other words,we may live on top of a gigantic, “natural”nuclear power plant.
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51 A try B leave C turn D point 52 A create B receive C feel D overcome 53 A work B solution C job D patterns 54 A whether B what C why D how 55 A from B within C of D to
56 A followed B dominated C restored D opposed 57 A ideas B demands C phenomena D movements 58 A things B acts C methods D records 59 A taken B benefited C left D kept 60 A after B before C since D when
61 A expanded B modified C gained D melted 62 A size B origin C structure D shape
63 A radical B traditional C classical D conventional 64 A system B copy C model D compound 65 A charge B last C experience D show 参考答案：
51．C 52．A 53．D 54．B 55．C 56．B 57．A 58．D 59．C 60．A 61．C 62．B 63．A 64．D 65．C
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