阅读下面的短文。短文中有 15个空白，在文章的后面，每一个空白都列了 4个备选答案。请根据文章的内容选择合适的词或短语填在空白处。
Singing Alarms Could Save the Blind
If you cannot see, you may not be able to1 find your way out of a burning building — and that could be fatal. A company in Leeds could change all that2 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 residential 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 where 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,” 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 of3 a large 8 room. It 9 them nearly four 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 pinpointed more easily than the source of a narrow band. Alarms 13 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.
词汇： directional /di5rekFEnEl/ adj. 定向的 thermal-imaging热效应成像 exit /5eksit/ n. 出口 pinpoint /5pin7pCint/ v. 精确地确定 install /in5stC:l/ v. 安装 concept /5kCnsept/ n. 概念，观念 residential /7rezi5denFEl/ adj. 居住的 emergency /i5mE:dVnsi/ n.紧急情况 static /5stAtik/ n. 静电噪音 grant /^rB:nt/ n. 授予物，准许potential /pE5tenF(E)l/ n. 潜力 注释：
1.在谓语动词中，不能并列使用两个情态动词，如 may和 can就不能并列使用。如果由于表达需要，要同时用“可能”和“能够”，就得说(写)成 may be able to。 I may be may be able to come tomorrow, but 1 cannot promise. 我可能明天来，但我不可能作出承诺。 2. that指第一句所表达的意思。
3. … find their way out of…：意为“找到从……出去的路”。练习：
1. A without B with C having D selling
2A 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 on B and C but D otherwise
15. A developed B determined C discovered D delivered
