GMAT写作辅导：109题Argument范文（二十一）

　　In this argument the author concludes that drinking Saluda Natural Spring Water is preferable to drinking tap water. Three reasons are offered in support of this conclusion: SNSW contains several of the minerals necessary for good health, it is completely tree of bacteria, and residents of Saluda―the town where it is bottled―are hospitalized less frequently than the national average. This argument is unconvincing because it relies on a variety of dubious assumptions.

　　The first questionable assumption underlying this argument that tap water does not contain the minerals in question and is not completely free of bacteria. This assumption is not supported in the argument. If tap water is found to contain the same minerals and to be free of bacteria, the authors conclusion is substantially undermined.

　　A second assumption of the argument is that the water residents of Saluda drink is the same as SNSW. Lacking evidence to the contrary, it is possible that Saluda is not the source of the bottled water but is merely the place where SNSW is bottled. No evidence is offered in the argument to dispute this possibility.

　　Finally, it is assumed without argument that the reason residents are hospitalized less frequently than the national average is that they drink SNSW. Again, no evidence is offered to support this assumption. Perhaps the residents are hospitalized less frequently because they are younger than the national average, because they are all vegetarians, or because they exercise daily. That is, there might be other reasons than the one cited to account for this disparity.

　　In conclusion, this is an unconvincing argument. To strengthen the conclusion that SNSW is more healthful than tap water, the author must provide evidence that tap water contains harmful bacteria not found in SNSW. Moreover, the author must demonstrate that the residents of Saluda regularly drink the same water as SNSW and that this is why they are hospitalized less frequently than the national average.