PASSAGE 20
　　Singing Alarms Could Save the Blind
　　If you cannot see, you may not be able to find your way out of a burning building-and that could be fatal. A company in Leeds could change all that__1__ directional sound alarms capable of guiding you to the exit.
　　Sound Alert, a company__2__ the University of Leeds, is installing the alarms in a residential¹ home for__3__ people in Sommerset and a resource centre for the blind in Cumbria.__4__produce a wide range of frequencies that enable the brain to determine the __5__ is coming from.
　　Deborah Withington of Sound Alert says that the alarms use most of the frequencies that can be __6__ by humans. "It is a burst of white noise__7__ people say sounds like static on the radio," he says. "Its life-saving potential is great"
　　She conducted an experiment in which people were filmed by thermal-imaging cameras trying to find their way out of a large__8__ room. It__9__ them nearly our minutes to find the door__10__ a sound alarm, but only 15 seconds with one.
　　Withington studies how the brain__11__ sounds at the university. She says that the __12__ of a wide band of frequencies can be pinpointed² more easily than the source of a narrow band. Alarms__13__ on the same concept have already been installed on emergency vehicles.
　　The alarms will also include rising or falling frequencies to indicate whether people should go up__14__ down stairs. They were__15__ with the aid of a large grant from British Nuclear Fuels.
　　1. A) without B)with C)having D)selling
　　2. A) run by B)changed by C) decorated by D)criticized by
　　3. A) slow B)deaf C)blind D)lame
　　4. A) Alarms B) Alarm C) The alarm D) The alarms
　　5. A) noise B) sound C) music D) bell
　　6. A) watched B) produced C) learnt D) heard
　　7. A) where B) what C) that D) how
　　8. A) smoked B) smoke-filled C) filled with smoke D) smoke-filling
　　9. A) has taken B) takes C) took D) will take
　　10. A) on B) near C) without D) from
　　11. A) processes B) produces C) possesses D) proceeds
　　12. A) feature B) quality C)diagram D) source
　　13. A) basis on B) base on C) basing on D) based on
　　14. A) or B) and C) but D) otherwise
　　15. A) developed B) determined³ C) discovered D) delivered
　　key: BACDB DCBCC ADDAA
　　PASSAGE 21
　　The Greatest Mystery of Whales
　　The whale is a mammal - warm-blooded, air-breathing, giving birth to its young alive, sucking them-and, like all mammals, originated on land. There are many signs of this. __1__ front flippers, used for steering⁴ and stability, are traces of feet.
　　Immense strength is built into the great body of the big whales, and in fact most of a whale's body is one gigantic muscle. The blue whale's pulling __2__ has been estimated at 400 horsepower. One specimen⁵ was reported to have __3__ a whaling vessel⁶ for seven hours at the __4__ of eight knots.
　　An enraged⁷ whale will attack a ship. A famous __5__ of this was the fate of whaler Essex, which was sunk __6__ South America early in the last century. More recently, steel ships have had their plates buckled⁸ in the same way. Sperm⁹ whales were known to __7__ the old-time whaleboats in their jaws¹⁰ and crush them.
　　The greatest mystery of whales is their diving ability. The sperm whale __8__ the bottom for his favourite food, the octopus¹¹. __9__ he is known to go as far down as 3,200 feet, where the pressure is 1,400 pounds, to the square inch. Doing __10__ he will remain submerged as long as one hour. Two feats¹² are involved in this : storing up enough __11__(all whales are air-breathed) and withstanding the great change in pressure. Just __12__ he dose it scientists have not determined. It is believed that some of the oxygen is stored in a special system of blood vessels¹³, rather than just held in the lungs. And __13__ that a special kind of oil in his head is some sort of compensating¹⁴ mechanism¹⁵ that automatically adjusts the internal pressure of his body. But __14__ you can't bring a live whale into the laboratory for study, no one __15__ just how these things work.
　　EXERCISE:
　　1. A)Their B)His C)Theirs D)Its
　　2. A)strength B)width C)height D)length
　　3. A)eaten B)crashed C)towed D)lifted
　　4. A)distance B)rate C)voyage D)sail
　　5. A)picture B)film C)example D)book
　　6. A)off the coast of B)of the coast of C0away the coast of D)in the coast of
　　7. A)hit B)seize C)damage D)overturn
　　8. A)sink to B)rest on C)dive to D)hide on
　　9. A)In that search B)Because of this C)In spite of that D)In support of this
　　10. A)so B)such C)above D)the same
　　11. A)air B)oxygen C)energy D)heat
　　12. A)what B)where C)how D)when
　　13. A)it is believed B)he believes C)we believe D)it believes
　　14. A)because of B)due to C)since D)owing to
　　15. A)communicates B)knows C)hears D)develops
　　KEY:D A C B C A B C A A B C A C B

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