单选题 It is hard to track the blue whale, the ocean's largest creature, which has almost been killed off by commercial whaling and is now listed as an endangered species. Attaching radio devices to it is difficult, and visual sightings are too unreliable to give real insight into its behavior.
So biologists were delighted early this year when, with the help of the Navy, they were able to track a particular blue whale for 43 days, monitoring its sounds. This was possible because of the Navy's formerly top-secret system of underwater listening devices spanning the oceans.
Tracking whales is but one example of an exciting new world just opening to civilian scientists after the cold war as the Navy starts to share and partly uncover its global network of underwater listening system built over the decades to track the ships of potential enemies.
Earth scientists announced at a news conference recently that they had used the system for closely monitoring a deep-sea volcanic eruption (爆发) for the first time and that they plan similar studies.
Other scientists have proposed to use the network for tracking ocean currents and measuring changes in ocean and global temperatures.
The speed of sound in water is roughly one mile a second-slower than through land but faster than through air. What is most important, different layers of ocean water can act as channels for sounds, focusing them in the same way a stethoscope (听诊器) does when it carries faint noises from a patient's chest to a doctor's ear. This focusing is the main reason that even relatively weak sounds in the ocean, especially low-frequency ones, can often travel thousands of miles.
单选题 The passage is chiefly about______ .
  • A. an effort to protect an endangered marine species
  • B. the civilian use of a military detection system
  • C. the exposure of a U. S. Navy top-secret weapon
  • D. a new way to look into die behavior of blue whales
【正确答案】 B
【答案解析】[解析] 本题属于文章的主旨题。首先我们可以排除A选项an effort to protect an endangered marine species和D选项a new way to look into the behavior of blue whales，因为文章举出蓝鲸的例子只是为了说明军用设施的民用，而不是把精力主要集中在蓝鲸或者对它的保护上面，因此这两个选项是不正确的。现在对比B选项the civilian use of a military detection system和C选项the exposure of a U． S． Navy top-secret weapon。B选项符合上面所做的分析，我们暂且保留。看C选项是否也符合题意。C选项的意思是：美国海军一项机密武器的曝光，如果文章是这个主题的话，那么文章中肯定会大谈特谈有关top-secret weapon的事情，但文章中没有，所以这个选项不如B选项好，我们选B。
单选题 The underwater listening system was originally designed______ .
  • A. to trace and locate enemy vessels
  • B. to monitor deep-sea volcanic eruptions
  • C. to study the movement of ocean currents
  • D. to replace the global radio communications network
【正确答案】 A
【答案解析】[解析] 本题后细节性问题。文章中与之对应的句子是：Tracking whiles is but one example of an exciting new world just opening to civilian scientists after the cold war as the Navy start to share and partly uncover its global network of underwater listening system built over the decades to track the ships of potential enemies．和上面的句子最接近的选项应当是A选项to trace and locate enemy vessels。其余的三个选项都没有出现在这段话中，因此我们可以轻松把它们排除。
单选题 The deep-sea listening system makes use of______ .
  • A. the sophisticated technology of focusing sounds under water
  • B. the capability of sound to travel at high speed
  • C. the unique property of layers of ocean water in transmitting sound
  • D. low-frequency sounds traveling across different layers of water
【正确答案】 C
【答案解析】[解析] 本题届细节性问题。对比四个选项，看哪一个最接近原文。阅读这四个选项，我们发现它们都和sound有关，因此，我们要找到文章中有关sound的叙述，是在文章的最后一段。现在对比四个选项，看哪个选项和这段内容最接近。A选项the sophisticated technology of focusing sounds under water中的sophisticated technology在这一段中没有出现，因此这个选项不好。B选项the capability of sound to travel at high speed在文中也没有体现，因此这个选项也不好。C选项the unique property of layers of ocean water in transmitting sound中的关键词layers在文章中提到了，这个选项和文中的内容没有多大的差异，暂且保留。D选项low frequency sounds traveling across different layers of water中的有关声音的 frequency问题没有提到，因此这个选项也不如C选项好，最好的选项应当是C。
单选题 It can be inferred from the passage that______ .
  • A. new radio devices should be developed for tracking the endangered blue whales
  • B. blue whales are no longer endangered with the use of the new listening system
  • C. opinions differ as to whether civilian scientists should be allowed to use military technology
  • D. military technology has great potential in civilian use
【正确答案】 D
【答案解析】[解析] 本题属于推理性问题。这个问题我们也只有对比四个选项从中选出一个比较好的。首先我们可以排除A选项new radio devices should be developed for tracking the endangered blue whales和B选项blue whales are no longer endangered with the use of the new listening system，在前面的分析中我们已经说过，蓝鲸在本文中只是作为一个例子出现的，不可能成为文章的主题或推论的对象，因此这两个选项我们可以轻松排除。现在只剩下C选项opinions differ as to whether civilian scientists should be allowed to use military technology和D选项military technology has great potential in civilian use。在对比这两个选项时，我们发现D选项和第一题的答案是完全一样的，我们从文章中完全可以推论出这一点，因此最好的选项应当是D。
单选题 Which of the following is true about the U. S. Navy underwater listening network?
  • A. It is now partly accessible to civilian scientists.
  • B. It has been replaced by a more advanced system.
  • C. It became useless to the military after the cold war.
  • D. It is indispensable in protecting endangered species.
【正确答案】 A
【答案解析】[解析] 本题属细节性问题。文中与之相关的句子是Tracking whales is but one example of an exciting new world just opening to civilian scientists after the cold war as the Navy starts to share and partly uncover its global network of underwater listening system built over the decades to track the ships of potential enemies．现在我们对比四个选项，看有没有和这段话比较接近的选项。在这四个选项中，只有A选项It is now partly accessible to civilian scientists和文中的内容比较像，比其它三个选项要好，因此我们选A。