高考◆英语◆广东省題庫下載題庫

the disastrous to the troubling. One such experiment took place in South America about fifty years

ago. Whether its final consequences will cause serious damage or nothing more than a small trouble

still remains to be seen.

      The story began in 1956 when an American scientist working in Brazil decided to solve the

problem of increasing the productivity of that country's bees. He imported a very active type of Afri-

can bee from Tanzania and mated  (交配)  it with the more easy-going native variety to produce a

new kind of bees. The new bees worked harder and produced twice as much honey. It seemed that

Professor Kerr, for that was the scientist's name, had a total success on his hands.

      Then things began to go wrong. For some reason as yet unseen, but perhaps as a result of

something in their environment, the new bees began to develop extremely attacking personali-

ties. They became bad-tempered and easy to be angry, attacked the native bees and drove them

from their living places.

      But worse was to follow. Having taken over the countryside, the new bees, with their danger-

ous stings (叮) , began to attack its neighbours -- cats, dogs, horses, chickens and finally man

himself.                                                               A long period of terror began that has so far killed a great number of animals and about

                    150 human beings.

     This would have been bad enough if the bees had stayed in Brazil. But now they are on the

move, heading northwards in countless millions towards Central and North America, and moving at

the alarming speed of 200 miles a year. The countries that lie in their path are naturally worried

because it looks as if nothing can be done to stop them.