2022年职称英语考试理工类(A级)试题及答案(6)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 fishFor the people in the northwestern Cameroon，however, the image isvery different. For them，lakes may mean terrible disasters. In 1984，poisonous gases explodedout of Lake Monoun and came down into the nearby villages，killing thirtyseven peopleTwoyears later,Lake Nyos erupted A cloud of gases rolled down the hills and into the valleys andkilled 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 arenot active anymore. However, poisonous gases from the center of the earth continue to flow upthrough cracks in the bottom of the lake. This is normal in a crater lake. In most crater lakes，thesegases are released often because the waterturns overregularlyThat is，the water from thebottom 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 overNo one knows the reason for this fact，but as a result，these lakes have more gases tapped at the bottom than othercrater lakes. In fact，scientists who have studied Lakes Nyos and Monoun have found 16,000times more gasesWhen a strong wind，cool weather a storm，or a landslide(滑坡)causes thewater 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 away to reduce the gas pressure at the bottom of Lake NyosThey stood a 672-foot plastic pipe inthe middle of the lake，with one end of the pipe near the bottom and the other end in the airNearthe top of the pipe，the team put several holes that could be opened or closed by a computerNow，when the gas pressure gets too high，the holes are opened and some of the gas-filled water shootsup through the pipe into the air like a fountainWith less pressure，a disastrous explosion is muchless likelyHowever, the scientists are not sure that one pipe will be enough to prevent explosionsThey 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 placethe scientists have installed early warning systems at both lakes. If the gas pressure rises to a dangerous level，computers will setoff loud sirens(警报)and bright lights to warn the people in the villagesThat way, they willhave time to escape from the dangerous gases41 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 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 becauseA the gases rise to the top and mix with airB people from the villages turn over the waterC scientists have put in a computer systemD they have more gases trapped at the bottom than other crater lakes44 A team of scientists hasA erected a pressure-releasing pipe in the lakeB identified the gases at the bottom of the lakeC built a beautiful fountain near the lakesD removed all dangerous gases from the lakes45 What do we learn from the last paragraph?A Scientists are planning to install pipes in all crater lakesB Scientists still do not know how to prevent gas explosionsC Explosion disasters could be avoided in the futureD Warning systems have been set up in the villages nearby