题目内容：
根据下列文章,请回答题。Singing Alarms Could Save the BlindIf 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 ___________(1) all that with directional(定向的) sound alarms capable of guiding you to the exit.
Sound Alert, a company run _________(2) the University of Leeds, is installing the alarms in a residential home for _________(3) people in Sommerset and a resource centre for the blind in Cumbria. The alarms produce a _________ (4) range of frequencies that enable the brain to_________ (5) where the sound 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 that people say sounds like static (静电噪音) on the radio," she says. "Its life-saving potential is_________ (7)."
She conducted an experiment in which people were filmed by thermal-imaging (热效应成像) cameras trying to find their _________ (8) out of a large smoke-filled room. It_________ (9) them nearly four minutes to find the door without a sound alarm,_________ (10) 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 pinpointed (精确地确定) 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_________ (14) whether people should go up or down stairs. They were_________ (15) with the aid of a large grant from British Nuclear Fuels. A．change
B．cure
C．demand
D．set
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