section c news broadcast

　　questions 11 and 12 are based on the following news.at the end of the news item，you will be given 30 seconds to answer the two questions.

　　now listen to the news.

　　11.the two koreans signed a deal to allow____ .

　　a.reunion of the two nations b.reunion of the governments

　　c.reunion of families separated d.return of former south korean prisoners

　　12.the reports said that____ .

　　a.a delegation was to travel to seoul

　　b.100 north koreans would visit relatives in pyongyong

　　c.the two sides agree to repatriate part of dprk prisoners formerly held in the south

　　d.the two sides agree to send home all dprk prisoners formerly held in the south

　　questions 13 to 15 are based on the following news.at the end of the news item，you will be given 45 seconds to answer the three questions.

　　now listen to the news.

　　13.government officials ordered a plant in japan to halt production because ____.

　　a.its product left people with food poisoning

　　b.the plant is going bankrupt

　　c.its milk products don't sell well

　　d.it has too limited a production which only serves 8，000 people

　　14.____ is not one of the symptoms after drinking low-fat milk produced by snow brand milk products co.ltd.

　　a.headache b.stomache pains c.bowel disturbance d.vomiting

　　15.in the summer of 1996，o-157 bacteria left ____ with food-poisoning.

　　a.more than 8，000 people b.exactly 8，282 people

　　c.more than 9，500 people d.all together about 18，000 people

　　section d note-taking & gap-filling

　　in this section you will hear a mini-lecture. you will hear the lecture once only.while listening to the lecture，take notes on the important points.your notes will not be marked，but you will need them to complete a 15-minute gap-filling task on answer sheet one.use the blank paper for note-taking.

　　part ⅱ proofreading & error correction ［15 min.］

　　proofread the given passage on answer sheet two as instructed.

　　part ⅲ reading comprehension ［40 min.］

　　section a reading comprehension ［30 min.］

　　in this section there are six reading passages followed by a total of fifteen multiple-choice questions.read the passages and then mark your answers on your coloured answer sheet.

　　text a

　　black holes

　　the theory of stellar evolution predicts that when the core of a star has used up its nuclear fuel，the core will collapse.if the star is about the size of the sun，it will turn into a degenerate dwarf star.if it is somewhat larger，it may undergo a supernova explosion that leaves behind a neutron star.but if the stellar core has a mass greater than about three solar masses，gravitational forces overwhelm nuclear forces and the core collapses.since nuclear forces are the strongest repulsive forces known，nothing can stop the continued collapse of the star.a black hole in space is formed.

　　because of the intense gravitational forces near the black hole，nothing can escape from it，not even light.if we were to send a probe toward an isolated black hole，the probe would detect no radiation from the black hole.it would，however，sense a gravitational field like the one that would be produced by a normal star of the same mass.as the probe approached the black hole，the gravitational forces would increase inexorably.at a distance of a few thousand kilometers，the gravitational forces would literally be torn away from the side furthest away from the black hole.eventually，at a distance of a few kilometers from the black hole，the particles that made up the probe would pass the point of no return，and the particles would be lost forever down the black hole.this point of no return is called the gravitational radius of the black hole.

　　but how can we hope to observe such an object？nature，herself，could conceivably provide us with a “probe” of a black hole：a binary star system in which one of the stars has become a black hole and is absorbing the mass of its companion star.as the matter of the companion star fell into the black hole，it would accelerate.this increased energy of motion would be changed into heat energy.near the gravitational radius the matter would move at speeds close to the speed of light，and temperatures would range from tens of millions of degrees to perhaps as much as a billion degrees.at these temperatures，x and gamma radiation are produced.further，since the matter near the gravitational radius would be orbiting the black hole about once every millisecond，the x radiation should show erratic，short-term variability unlike the regular or periodic varability associated with neutron stars and degenerate dwarfs.

　　the x -ray source cygnus x-1 fulfills these “experimental” conditions.it is part of a binary star system in which a blue supergiant star is orbiting an invisible companion star.this invisible companion has a mass greater than about nine times the mass of the sun，and it is a strong x-ray source that shows rapid variations in the intensity of its x-ray flux.most astronomers believe that cygnus x-1 is a black hole but this belief is tempered with a dose of caution.the idea of a black hole is still difficult to swallow，but theorists can think of no other object that could explain the phenomenon of cygnus x-1.for this reason，in most scientific papers，cygnus x-1 is referred to simply as a black hole “candidate.”

　　16.according to the passage，a black hole would.

　　a.be observable through a powerful telescopeb.be invisible even at close range

　　c.be formed from a degenerate dwarf stard.be most likely to develop in a binary star system

　　17.the author regards the existence of black holes as ____.

　　a.experimentally confirmed b.a logical contradiction

　　c.theoretically possible d.in principle unprovable

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