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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. The underwater listening system was originally designed ________.
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Questions 1 to 3 are based on the following conversation. At the end of the conversation, you will be given 15 seconds to answer the questions. When buying an insurance policy, what is NOT necessary
Questions 21 and 22 are based on the following news. At the end of the news item, you will be given 10 seconds to answer the questions. Where was this meeting held
Do you wake up every day feeling too tired, or even upset If so, then a new alarm clock could be just for you.The clock, called SleepSmart, measures your sleep cycle, and waits (1) you to be in your lightest phase of sleep (2) rousing you. Its makers say that should (3) you wake up feeling refreshed every morning.As you sleep you pass (4) a sequence of sleep states—light sleep, deep sleep and REM(rapid eye movement) sleep—that (5)f approximately every 90 minutes. The point in that cycle at which you wake can (6) how you feel later, and may (7) have a greater impact than how much or little you have slept. Being roused during a light phase (8) you are more likely to wake up energetic.SleepSmart (9) the distinct pattern of brain waves (10) during each phase of sleep, via a headband equipped (11) electrodes (电极)and a microprocessor. This measures the electrical activity of the wearer’s brain, in much the (12) way as some machines used for medical and research (13) , and communicates wirelessly with a clock unit near the bed. You (14) the clock with the latest time at (15) you want to be wakened, and it (16) duly(适时地)wakes you during the last light sleep phase before that.The (17) was invented by a group of students at Brown University in Rhode Island (18) a friend complained of waking up tired and performing poorly on a test. " (19) sleep-deprived people ourselves, we started thinking of (20) to do about it," says Eric Shashoua, a recent college graduate and now chief executive officer of Axon Sleep Research Laboratories, a company created by the students to develop their idea. 11().
中外合作者在合作企业合同中约定合作期满时合作企业的全部固定资产归中国合作者所有的，可以在合作企业合同中约定外国合作者在合作期限内先行回收投资的办法。外国合作者在合作期限内先行回收投资的，仍应当依照合作企业合同的约定对合作企业的债务承担责任。( )
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