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沙发

楼主 |
发表于 2012-9-9 20:50:52
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跟进自己写的文章,求意见和指导!
The author of this argument tries to persuade people that the decline of amphibians in Xanadu National Park is caused by the introduction of trouts, which are known to eat amphibian's eggs. This notion may seem all right at first sight, but unfortunately, the author fails to give enough evidence to prove that trouts are the only cause of amphibian's decline.
While the author blames the decline of amphibians on the trouts, the amphibians are not necessarily decimated in fact. Since the correctness of the two observations in the year 1975 and 2002 is not certain, we can never base our assumptions on this uncertainty. We may need far more information to make sure of the decline of amphibians instead of one conclusion from one group. A lot of possibilities may take place to impair these two observations. Are they done based on the same standard? Perhaps the investigation of 1975 was done within one year while the one in 2002 only lasted a few days? Are these two done with the same equipment? Perhaps the effective exploring equipment has been outdated and ineffective at all in 2002? Are they done by the same flock of people? Perhaps the experienced scholars in 1975 have retired in 2002 and some novice people take this job over in the second research. But, what I mentioned is not explained in the argument. As a result, we are allowed to have doubts on the credibility of the assertion that amphibians are becoming less and less.
And even though amphibians are getting decreased, are these trouts necessarily to blame? What we only know about the trouts is that they eat eggs of amphibians, but they can only succeed in eating those eggs under certain circumstances. Without enough evidence to show the capability of eating eggs, no hasty conclusion can be achieved. And there are, in deed, a lot of chances that trouts can never eat eggs of amphibians. For example, trouts introduced in 1975 were all put in lake A in Xanadu Park while amphibians were living near other lakes. Even if these two species lived together, there may be other adversaries of trouts living in Xanadu Park, which imposed some restriction on trouts and protected the amphibian eggs to some extent. Or, trouts have more preferred food than amphibians' eggs near their reach so that they only eat quite a few eggs.
In addition, it is not appropriate for us to consider the trouts as the only reason of amphibians' decline, even if trouts really do harm to the number of amphibians. As the author mentioned, lives of amphibians were threatened globally due to the polluted air and water. But no evidence is given in the argument that the amphibians in Xanadu Park were not victims of the bad environment. At least, a credible scientific report from trustworthy institutions have to prove the good quality of water and air in Xanadu Park. Or, is there any other possibility for these poor amphibians? What if they contracted a pervasive disease among amphibians and die of this ailment? What if they lives are hampered by some secret animal hunting gangs in order to make money? Since there is no further explanation, there may be other reason for amphibians' decline.
In all, the author has to find out more evidence to prove what he advocates is true. He or she needs evidence to show that amphibians are really declining, the trouts in Xanadu really threaten amphibians' live seriously, and no more reasons should be responsible for amphibians' reduction in Xanadu. |
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