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 you to 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 (静电噪声) 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.

As possibly the galaxy’s (银河) most massive star, Eta Carinae is now engaging in some very unusual behaviour. Australian astronomers, being in the Southern Hemisphere (半球), are able to observe it clearly.
In the 19th century, Eta Carinae was for a time the third brightest star in the sky. It has now become less bright so that binoculars (双筒望远镜) are needed to see it. "It seems to be brightening and becoming less bright over a period of many years", said Dr Bob Duncan from the Australia Telescope National Facility.
While it is not unusual for stars to vary in brightness, the period is usually much shorter. "Since 1992 it has become four times brighter, and then last year it began to drop dramatically," he said.
The problem in observing Eta Carinae is that it has been surrounded by a cloud of gas and dust, making it hard to see the star directly. However, radio waves and infrared light (红外线) can pass through this cloud, so telescopes that receive these wavelengths can observe what is occurring.
Eta Carinae is of particular interest to astronomers because it seems to be in its death throes (剧痛). Being so large it will end up as a supernova (超新星). There has not been a supernova in our galaxy since the invention of the telescope. While a 1987 explosion in a nearby galaxy gave astronomers plenty of valuable data, they are hungry for an even closer look.
Eta Carinae has other unique features, and is the only star known to produce an ultraviolet (紫外线) laser that is brighter than that produced by the Sun. Lasers have been observed in other frequencies from a few stars.

A．they were so dependent on potatoes that they refused to eat anything else.
B．they were forced to leave their homeland and move to America.
C．the weather conditions in Ireland were not suitable for growing potatoes.
D．the potato harvest was bad.