共用题干 Singing Alarms Could Save the Blind.If you cannot see,you may not be able to find your way out ...

共用题干
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______(51)directional sound alarms capable of guiding you to the exit.
Sound Alert,a company______(52)the University of Leeds,is installing the alarms in a residential home for______(53)people in Sommerset and a resource centre for the blind in
Cumbria.______(54)produce a wide range of frequencies that enable the brain to determine where the______（55)is coming from.
Deborah Withington of Sound Alert says that the alarms use most of the frequencies that can be______（56)by humans."It is a burst of white noise ______(57)people say sounds like static on the radio,"she 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______(58)room. It______(59)them nearly four minutes to find the door______(60)a sound alarm,but only 15 seconds with one.
Withington studies how the brain______(61)sounds at the university. She says that the _______(62)of a wide band of frequencies can be pinpointed more easily than the source of a narrow band .Alarms______(63)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______(64)down stairs.They were______（65)with the aid of a large grant from British Nuclear Fuels. 56._________