- 最后登录
- 2013-3-16
- 在线时间
- 31 小时
- 寄托币
- 86
- 声望
- 0
- 注册时间
- 2008-8-29
- 阅读权限
- 10
- 帖子
- 0
- 精华
- 0
- 积分
- 27
- UID
- 2538756
- 声望
- 0
- 寄托币
- 86
- 注册时间
- 2008-8-29
- 精华
- 0
- 帖子
- 0
|
P372-373页的例子没有给出答案,感觉不大好写,花了挺长时间写出来的,还是感觉很烂,大家使劲拍吧!
Reading:
The discovery of penicillin and other antibiotic drugs is the most dramatic medical development of the twentieth century. These new drugs quickly become known as "wonder drugs" because they saved so many lives that were threatened by major forms of infection. The research that led to their development rested on the belief that chemicals could be found that would destroy specific microorganisms without injuring the human body at the same time. Advances in chemistry and in the knowledge of bacteria quickened the discovery of such chemicals.
In 1933, the first of the sulfa drugs, prontosil, was tested clinically on humans and was found to cure blood infections that would otherwise have been fatal. In 1941, the first successful human tests of penicillin were conducted on cases of streptococcus infections. The discovery of penicillin laid the foundation for even more powerful weapons against specific diseases. Within the next decade, researchers identified some 200 antibiotic substances that were effective against one or another type of bacteria. One of the most important was streptomycin, found to be potent against tuberculosis and other infections that were not affected by penicillin.
Antibiotics gave the medical profession powerful tools that could directly fight a very wide r a n p of specific diseases. They made possible he survival of patients during and after surgery No longer was it necessary to depend largely on the body's own immune system to fight off major infections; these infections could be attacked directly with drugs. Among the most spectacular effects of antibiotics were reductions in the number of deaths from pneumonia and tuberculosis.
听力原文:
(Narrator) Now listen to part of a lecture in a biology class.
(Professor)
As soon as we developed antibiotics, new strains of bacteria appeared that were resistant to some or all of the drugs. Hospitals started using antibiotics regularly in the 1950s, but resistance stand appearing within a few years. Today, once third of the patients in hospitals are on antibiotics, but antibiotic resistance is increasing the danger of hospital infections--to the point where people are almost safer staying home than going to a hospital.
In the forties, penicillin really was a wonder drug. Back then, you could give a patient with bacteria1 pneumonia ten thousand units of penicillin four times a day and cure the disease. Today, you could give 24 million units of penicillin a day, but the patient might still die. Why? Well, in a way, bacteria are smarter than us. They evolve to counteract any drug we attack them with. A lot of bacteria are now completely resistant to penicillin.
Bacteria can evolve very effective weapons against antibiotics. Some of them develop enzymes to match every antibiotic we throw at them. All these weapons and counter-weapons match one another--just like the weapons in real military warfare. So, no matter what antibiotic we use, the bacteria will come up with a way to make it useless.
How dues this happen? Well, if you douse a colony of bacteria with an antibiotic, the colony will be killed—that is all except for a few cells. A Few cells will survive because they carry a resistance gene for that particular antibiotic. The surviving cells quickly multiply, and they pass along this lucky gene to their offspring. And soon you have a new stain of bacteria that's resistant to that drug.
One consequence of antibiotic resistance is the reappearance of tuberculosis as a major illness. Twenty years ago, doctors thought tuberculosis was a defeated disease. Since then, however, new casts of tuberculosis have increased by 20 percent. And several strains of the disease are resistant to any drug we can attack them with.
(Narrator) Summarize the main points made in the lecture, explaining how they differ from points made in the reading.
我写的文章:
Unlike the positive attitude of the author to antibiotics, the lecturer does not have much confidence about it. The professor points out in the beginning of her lecture that resistance to antibiotics was developed by new strains of bacteria soon after these antibiotics were developed.
Penicillin was a wonder drug in the forties, as the author stated in the passage, but a patient will still die, the professor argues, after using tremendous dose of penicillin, because resistance to penicillin. The professor then discusses, in general, that bacteria can develop effective weapons against antibiotics and fail any antibiotics we attack them with.
In addition, the lecturer demonstrates the procedure how bacteria evolve such weapons against antibiotics. When we douse a colony of bacteria with an antibiotic, most part of the colony will be killed except a few cells that carry a resistance gene. These cells will duplicate themselves quickly and their offspring will inherit this gene. As a result, this antibiotic no longer has effect on them. The lecturer then gives an example about this. The reappearance of tuberculosis as a major disease due to antibiotic resistance, while 20 years ago doctors thought that we have successfully conquered this disease. Furthermore, new cases of tuberculosis even increased by 20% since the reappearance of tuberculosis.
In sum, the war between human beings and bacteria is not such a easy one as the author believes. |
|