gre写作复习资料：gre写作范文14

　　As people grow older, an enzyme known as PEP increasingly breaks down the neuropeptide chemicals involved in learning and memory. But now, researchers have found compounds that prevent PEP from breaking neuropeptides apart. In tests, these compounds almost completely restored lost memory in rats. The use of these compounds should be extended to students who have poor memory and difficulty in concentrating-and therefore serious problems in school performance. Science finally has a solution for problems neither parents nor teachers could solve.

　　In this argument, the arguer states that researchers have found compounds that keep an enzyme known as PEP from breaking neuropeptides apart, which are known to be involved in learning and memory. The arguer states that tests have shown that these compounds almost completely restored lost memory in rats, and that therefore, these compounds should be administered to students with poor memory and difficulty in concentrating. This argument is unconvincing because it contains several critical flaws in logic.

　　First of all, the arguer states that as people grow older, PEP breaks down the neuropeptide chemicals that are involved in learning and memory. It is true that generally, as people get older, they tend to have more problems with learning and memory. However, there is no direct link mentioned between the breaking down of the neuropeptide chemicals and the loss of learning ability or memory. Additionally, the arguer mentions neuropeptide chemicals that are broken down by PEP. What the researchers have found is a compound that prevents neuropeptides from breaking apart. These are two different physical actions: the breaking down of neuropeptide chemicals as opposed to the breaking apart of the neuropeptides themselves. Furthermore, it is not stated which of these physical actions is involved with the loss of learning ability and memory. It is not explicitly stated that the breaking down of chemicals causes a loss in learning ability and memory, only that this happens as people grow older. It is also not expressly stated whether the breaking apart of the neuropeptides themselves causes memory loss or a lessened learning ability. Without showing a direct link between the effect of keeping the neuropeptides from breaking apart and a reduction in the loss of memory and learning ability, the efficacy of the compounds is called into question.

　　Secondly and most obviously, the compounds were only tested on rats. Rats may have a similar genetic structure to humans, but they are most certainly not the same as humans. There may be different causes for the learning and memory problems in rats as opposed to that of humans. The effect of the compounds on rats may also be very different from their effect on human beings. It is absurd in the extreme to advocate giving these compounds to students, even assuming that they would help the students with their studies, without conducting further studies assessing the compounds’ overall effects on humans. The argument fails on this particular fact if for no other reason.

　　Additionally, the arguer begins his or her argument by stating that "as people grow older", PEP breaks down the neuropeptide chemicals involved in learning and memory. At the end of the argument, the arguer advocates extending the compounds that prevent PEP from breaking neuropeptides apart to students who have poor memory and difficulty in concentrating. Students are generally young, not older people. There is no evidence presented that shows what actually causes students to have a poor memory or difficulty in concentrating. Indeed, it is more likely that it is extracurricular activities or a lack of sleep that causes such problems in students, not a problem associated with aging. It is highly unlikely that even if the stated compounds could help prevent the memory loss and decreased learning ability associated with aging that it would have any benefits for students.

　　In summary, the arguer fails to convince with the argument as presented. To strengthen the argument, the arguer must show a direct link between the breaking apart of neuropeptides and loss of memory and learning ability. Additionally, he or she must show that students’ poor memory and difficulty in concentrating is a result of the same process, and that the researcher’s compounds would have as beneficial an effect on humans as it seems to have on rats.