根据材料，回答题。 Singing Alarms Could Save the BlindIf you cannot see， you may not be able

根据材料，回答题。

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. _________ （52 ） 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 hkestatic 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 mote 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 failing frequencies to indicate whether people should goup_________ （64） down stairs. They were _________ （65 ） with the aid of a large grant from British

Nuclear Fuels.

回答（51）题 查看材料

A.without

B.with

C.having

D.selling