首页
财务会计
医药卫生
金融经济
考公考编
外语考试
学历提升
职称考试
建筑工程
IT考试
其他
登录
职称考试
共用题干 The Exploding Lakes of CameroonWhat comes to mind when you think of a l...
共用题干 The Exploding Lakes of CameroonWhat comes to mind when you think of a l...
admin
2020-12-24
13
问题
共用题干
The Exploding Lakes of Cameroon
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 trapped 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.In that way,they will have time to escape from the dangerous gases.
选项
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
答案
D
解析
第一段第五、六、七句提到,Monoun湖在1984年喷发出了有毒气体,两年后,Nyos湖喷发时也出现类似情况,因此选择B项。
根据第二段倒数第二句可知,大多数火山口湖中的湖水会翻转,使有毒气体得以释放,而第三段第一句又表示,Nyos和Monoun中的湖水不会翻转。由此可知,Nyos和Monoun与其他的火山口湖不同。
根据第三段第二句可知,虽然没人知道原因,但是与其他火山口湖相比,Nyos和Monoun的湖底释放出了更多的气体。
根据第四段第三句“They stood a 672-foot plastic pipe in the middle of the lake , with oneend of the pipe near the bottom and the other end in the air.”可知,该科学家团队在湖里立了一根管子,管子的一端在湖底,另一端在空中。这样做是在利用连通器的原理来减小湖底压强,因此A项正确。
前文表明,湖里竖起若干根减小湖底压强的管子后,就不会再有毒气喷发的危险。最后一段又说在这些管子都到位前科学家在这两个湖附近安装了早期预警系统,以便人们有时间逃离这些有毒气体.由此可知,这种有毒气体喷发的灾难在未来可以避免。
转载请注明原文地址:https://ti.zuoweng.com/ti/QbfQKKKQ
相关试题推荐
共用题干 Inanagewhentechnologyisdevelopingfasterthaneverbefore,manype...
共用题干 Inanagewhentechnologyisdevelopingfasterthaneverbefore,manype...
共用题干 Thatscientistshaveclonedasheepsendsacademicsandthepublicinto...
共用题干 Thatscientistshaveclonedasheepsendsacademicsandthepublicinto...
共用题干 Thatscientistshaveclonedasheepsendsacademicsandthepublicinto...
共用题干 第三篇RaceCarDriversThemenwhoracethecarsaregenerallysmall,witha...
共用题干 第三篇RaceCarDriversThemenwhoracethecarsaregenerallysmall,witha...
共用题干 第三篇RaceCarDriversThemenwhoracethecarsaregenerallysmall,witha...
共用题干 第二篇LoveorHate?Wehavesavedasafinalsetofemotionstotwomostim...
共用题干 第二篇LoveorHate?Wehavesavedasafinalsetofemotionstotwomostim...
随机试题
下列关于增值税征税范围的说法,正确的有()。 A、股权转让不征收增值税 B、
根据《房屋建筑与装饰工程工程量计算规范》(GB50854-2013),下列关于砖
下列有关借款合同的说法,符合规定的是()。
在需求不足及经济衰退时期,为了刺激消费、拉动需求、促进经济增长,中央银行可采取的
风险识别的最主要成果是( )。
几年前,美国心理学博士艾尔森对世界100名各领域的杰出人士做了一项问卷调查,结果让他十分惊讶——其中61%的人承认,他们所从事的职业,并非他们最喜欢的,至...
老舍:鲁迅 A.英语:语文B.夏天:冰箱 C.冰心:金庸D.玉石:姚明
谈谈你对“多个朋友。多条路”的理解。
某临街住宅楼于2009年末建成,砖混结构,共6层,2年前经有关部门批准,该楼一层全部改为点铺或餐馆。经调查,一层产权人的经营方式有出租和自营两种情况。 ...
M国电信企业准备进军C国,对C国诸多条件进行了分析。目前C国电信行业迅速发展,网络规模居世界首位,网络装备和技术达到世界一流水平。C国人口众多,庞大的用户...