题目原文：
The cane toad is a large (1.8 kg) amphibian species native to Central and South America. It was deliberately introduced to Australia in 1935 with the expectation that it would protect farmers’ crops by eating harmful insects. Unfortunately, the toad multiplied rapidly, and a large cane toad population now threatens small native animals that are not pests. Several measures have been proposed to stop the spread of the cane toad in Australia.
One way to prevent the spread of the toad would be to build a national fence. A fence that blocks the advance of the toads will prevent them from moving into those parts of Australia that they have not yet colonized. This approach has been used before: a national fence was erected in the early part of the twentieth century to prevent the spread of rabbits, another animal species that was introduced in Australia from abroad and had a harmful impact on its native ecosystems.
Second, the toads could be captured and destroyed by volunteers. Cane toads can easily be caught in simple traps and can even be captured by hand. Young toads and cane toad eggs are even easier to gather and destroy, since they are restricted to the water. If the Australian government were to organize a campaign among Australian citizens to join forces to destroy the toads, the collective effort might stop the toad from spreading.
Third, researchers are developing a disease-causing virus to control the cane toad populations. This virus will be specially designed: although it will be able to infect a number of reptile and amphibian species, it will not harm most of the infected species; it will specifically harm only the cane toads. The virus will control the population of cane toads by preventing them from maturing and reproducing.
题目音频：
学术写作：
简化大意：
教授：保持健康最重要的方式？
Claire: a good diet 好的饮食习惯
Paul: regular checkups 定期体检
详细题目回忆：
Doctor Achebe:
In the next two weeks, we are going to be studying how biological discoveries have affected our lives. Research in biology provides us with a better understanding of how our bodies work. As an introduction to this topic, I would like for you to discuss among yourselves this question: What is the most important thing a person can do to maintain good health? Please explain why you think so.
Claire:
I feel very strongly that a good diet is the most important factor in maintaining good health. Eating good, healthy foods, especially green vegetables, gives your body the materials it needs to stay strong. Good nutrition is the key to good health.
Paul:
Most people don’t visit the doctor for regular checkups. Sure, if they feel sick, they go, but that’s not enough. During a yearly exam, a physician can help a patient address health issues before they become a larger problem. So I think preventive doctor visits are key to good health.
答案请付费后查阅：
