14．Extremophiles（極端微生物） are organisms that have been discovered on earth that survive in environments that were once thought not to be able to sustain life．These extreme environments include intense heat，highly acidic environments，extreme pressure and extreme cold．Different organisms have developed varying ways of adapting to these environments，but most scientists agree that it is unlikely that life on Earth originated under such extremes．
Adapting to Extreme Heat
In the 1960s，heat resistant bacteria were discovered in hot springs in Yellowstone National Park．This bacteria，thermus aquaticus thrives at temperatures of 70°C but can survive temperatures of 50°C to 80°C．A few years after these were discovered，other bacteria were found living under even more extreme conditions．Hydrothermal vents （熱水流火山口） were discovered deep in the ocean and under such high pressure that the water boils at 340°C．It was a surprise to researchers to discover bacteria living and thriving in the vents at such extreme temperatures and pressures．Not only were there bacteria，but centimeters away where the water was cooler，was a complete ecosystem living off the bacteria．There were clams and tubeworms among other species．
Adapting to Extreme Cold
Other extremophiles have developed ways to cope with cold．Deep ocean water is as a fairly constant temperature of 2°C，but because of its salt content，in colder areas，ocean water can reach temperatures as low at-12°C without freezing．Extremophiles known as psychrophiles（低溫微生物） are known to survive at these low temperatures．Different species have come up with different ways to survive these cold temperatures．Some have developed substances，such as glycerol（甘油） or antifreeze proteins which lower the freezing point of water by several degrees．
The main danger to organisms of freezing is the damage caused by ice crystals as water freezes and expands．Some species of frogs and turtles have proteins which actually facilitate the freezing of body liquids．If the animal's body liquids begin to freeze，a chain reaction is started and all of the body's liquids freeze rapidly．This prevents the formation of ice crystals large enough to do any damage．Many kinds of microorganisms can survive freezing and thawing，as long as the problem of ice crystals is avoided．
66．An"ecosystem"（paragraph 2）can be best described asA．
A．a(chǎn)n interacting community that contains both living and non-living organisms
B．a(chǎn) large collective term for animals that eat bacteria
C．different types of plants and animals that cooperate for food
D．the place where temperatures and conditions are dangerous and extreme
67．The formation of large ice crystal is dangerous mostly becauseC．
A．the animal can no longer breathe，and nutrient can't be carried around the body
B．proteins cause the animal's body liquids to freeze
C．the freezing and expansion of water could damage the animal's organs
D．the temperature inside the animal becomes too cold to survive in
68．Which of the following statements is FALSE according to the passage？D
A．Extremophiles live in environments other organisms cannot survive in．
B．Extremophiles can survive in both acidic and high pressure environments．
C．The thermophile lives in extremely high temperatures．
D．Fresh water has a constant temperature of around 2° C．
69．The purpose of this article is toC．
A．a(chǎn)muse and entertain scientists
B．provide a personal opinion about an issue
C．educate and inform readers
D．predict the beginning of evolution．
分析 本文屬于說明文閱讀，作者通過這篇文章主要向我們講述了地球上已經(jīng)發(fā)現(xiàn)了一些極端微生物，它們可以適應(yīng)高溫、高酸、高壓或者極端寒冷的環(huán)境，不同的生物有不同的發(fā)展適應(yīng)這些環(huán)境的方法．
解答 66．A．推理判斷題．根據(jù)文章第二段"Not only were there bacteria，but centimeters away where the water was cooler，was a complete ecosystem living off the bacteria"不僅有細(xì)菌，幾厘米遠(yuǎn)的地方還有低溫的水，是一個(gè)完整的生態(tài)系統(tǒng)；可知完整的生態(tài)系統(tǒng)是一個(gè)包括生物和非生物的有趣社區(qū)；故選A，
67．C．細(xì)節(jié)理解題．根據(jù)文章最后一段"The main danger to organisms of freezing is the damage caused by ice crystals as water freezes and expands"對生物體的主要危險(xiǎn)是凍結(jié)的冰晶和水結(jié)冰膨脹造成的損害；即生物體器官的損傷；故選C．
68．D．細(xì)節(jié)理解題．根據(jù)文章第三段"Deep ocean water is as a fairly constant temperature of 2°C"海洋深層水擁有相當(dāng)恒定的溫度2°C，可知淡水的恒定穩(wěn)定2°C是錯(cuò)誤的；故選D．
69．C．主旨大意題．通讀全文可知，文章主要講地球上已經(jīng)發(fā)現(xiàn)了一些極端微生物，并舉了例子，作者只是描述了已有事實(shí)，并沒有發(fā)表自己的意見，由此可見作者的目的旨在教育和告知讀者這些信息．故選C．
點(diǎn)評 考察學(xué)生的細(xì)節(jié)理解和推理判斷能力，做細(xì)節(jié)理解題時(shí)一定要找到文章中的原句，和題干進(jìn)行比較，再做出正確的選擇．在做推理判斷題不要以個(gè)人的主觀想象代替文章的事實(shí)，要根據(jù)文章事實(shí)進(jìn)行合乎邏輯的推理判斷．
