新概念第四册 Lesson 17 A man-made disease

日期:2010-04-29

  Lesson 17 A man-made disease

  人为的疾病

  First listen and then answer the following question.

  听录音,然后回答以下问题。

  What factor helped to spread the disease of myxomatosis?

  In the early days of the settlement of Australia, enterprising settlers unwisely introduced the European rabbit. This rabbit had no natural enemies in the Antipodes, so that it multiplied with that promiscuous abandon characteristic of rabbits. It overran a whole continent. It caused devastation by burrowing and by devouring the herbage which might have maintained millions of sheep and cattle. Scientists discovered that this particular variety of rabbit (and apparently no other animal) was susceptible to a fatal virus disease, myxomatosis. By infecting animals and letting them loose in the burrows, local epidemics of this disease could be created. Later it was found that there was a type of mosquito which acted as the carrier of this disease and passed it on to the rabbits. So while the rest of the world was trying to get rid of mosquitoes, Australia was encouraging this one. It effectively spread the disease all over the continent and drastically reduced the rabbit population. It later became apparent that rabbits were developing a degree of resistance to this disease, so that the rabbit population was unlikely to be completely exterminated. There were hopes, however, that the problem of the rabbit would become manageable.

小精灵儿童网站

  新概念第四册
 
 
子栏目导航
  • 哆啦A梦

    动画片
    哆啦A梦是一只来自未来世界的猫型机器人,用自己神奇的百宝袋和各种奇妙的道具帮助大雄解决困难。哆啦A梦的故事将人们带进一个奇妙、充满想像力的世界...

在线口算练习
电子课本
在线识字
关于我们 |  我的账户 |  隐私政策 |  在线投稿 |  相关服务 |  网站地图
Copyright © 2002-2019 All Rights Reserved 版权所有 小精灵儿童网站
联系我们(9:00-17:00)
广告和商务合作qq:2925720737
友情链接qq:570188905
邮件:570188905@qq.com