题目内容
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(51)all that with directional (定向的) sound alarms capable of guiding y0uto the exit.
Sound Alert, a company run(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. The alarms produce a(54)range of frequencies that enable the brain to(55)where the sound 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 that people say sounds like static (静电噪音) on the radio," she says. "Its life-saving potential is(57)."
She conducted an experiment in which people were filmed by thermal-imaging (热效应成像) cameras trying to find their(58)out of a large smoke-filled room. It(59)them nearly four minutes to find the door without a sound alarm,(60)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 (精确地确定) more easily than the source of a narrow band. Alarms(63)on the same concept have already been installed on emergency vehicles.
The alarms will also include rising or falling frequencies to(64)whether people should go up or down stairs. They were(65)with the aid of a large grant from British Nuclear Fuels.
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Less-educated people report fewer days of stress possibly because ______.
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A Thirsty World
The world is not only hungry; it is also thirsty for water. This seems strange to you, since nearly 75% of the earth's surface is covered with water. But about 97% of this huge amount is from sea water, or salt water. Man can only drink and use the other 3% — the fresh water that comes from rivers, lakes, underground, and other sources. And we cannot even use all of that, because some of it is in the form. of iceberg (冰山) and glaciers (冰串). Even worse, some of it has been polluted.
At the moment, this small amount of fresh water is still enough for us. However, our need for water is increasing rapidly. Only if we take steps to deal with this problem now can we avoid a severe worldwide water shortage later on. A limited water supply would have a bad effect on
agriculture and industry.
In addition to stopping wasting our precious water, one useful step we should take is to develop ways of reusing it. Experiments have already been done in this field, but only on a small scale.
Today, in most large cities tanks, water is used only once and it eventually returns to the sea or runs into underground storage tanks. But it is possible to pipe water that has been used to a purifying (净化) plant. There it can be filtered (过滤) and treated with chemicals so that it can be used again just as it were fresh from a spring.
But even if every large city purified and reused its water, we still would not have enough. Where could we turn next？ To the oceans! All we'd have to do to make use of the vast amount of sea-water is — remove the salt. This salt-removing process is already in use in many parts of the wodd.
The phrase "the word" in the first line of the passage refers to ______.
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