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
39
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
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.
答案
C
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/KbfQKKKQ
相关试题推荐
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 第二篇LoveorHate?Wehavesavedasafinalsetofemotionstotwomostim...
共用题干 第二篇LoveorHate?Wehavesavedasafinalsetofemotionstotwomostim...
共用题干 第二篇LoveorHate?Wehavesavedasafinalsetofemotionstotwomostim...
共用题干 第二篇LoveorHate?Wehavesavedasafinalsetofemotionstotwomostim...
共用题干 第三篇"Cleanyourplate!"and"Beamemberoftheclean-plateclub!"Just...Whic
随机试题
男,47岁,进食油煎鸡蛋后出现右上腹剧痛,并放射至右肩胛区,伴畏寒、发热,应考虑
目前在我国,采用无店铺经营模式的房地产经纪机构的业务范围主要有( )。
关系营销包含不同的层次。宾馆为常客提供免费服务或降价服务,依靠价格刺激维持顾客关
诺氟沙星的化学结构是
关于全口义齿修复时颌位关系的确定、最全面的说法是()A.恢复面部生理形态B.确定正确的颌间距离C.恢复髁突的生理后位和面部下1/3高度D.恢复
患者男,65岁。脑血栓致右侧肢体瘫痪卧床2年,因骶尾部皮肤破损而入院,入院后检查:破损处组织发黑,有脓性分泌物与臭味,面积5cmx6cm。 目前患者最...
芬太尼的临床应用是A、剧烈疼痛B、帕金森病C、癫痫小发作D、癫痫小发作E、风湿性关节炎
督导者老黄定期对社会工作者小田进行行政性督导,其中“工作监督”的任务是( )。A.进行工作授权B.鼓励被督导者参与机构政策规划C.安排被督导者的服务工作
根据《建设工程质量管理条例》,在正常使用条件下,下列建设工程中最低保修期限为2年的是(??)。A.基础设施工程B.屋面防水工程C.电气管线工程D.供热与供
甲公司2015年至2017年发生的有关交易或事项如下: (1)2015年6月30日,甲公司以一项固定资产和一项土地使用权作为对价,取得乙公司60%的股权...