29. This speaker argues that farmers who invested in organic farming equipment should resume synthetic farming because it is financially unwise to continue organic farming. The speaker cites studies showing that farmers who switched to organic farming last year had tower crop yields. Based on these studies, the speaker concludes that the relatively inexpensive investment in organic farming equipment cannot justify continuing to farm organically. The speaker also claims that continuing to farm organically is financially unwise because it is motivated by environmental, not economic, concerns. The argument suffers from three problems.来源：考试大
One problem with this reasoning involves the vague comparative claim that farmers who switched to organic farming fast year had lower crop yields. We are not informed whether the survey compared last year s organic crop yields with yields from previous years or with those from synthetic farms. Moreover, the author provides no evidence about how the survey was conducted. Lacking more information about the survey, we cannot accept the speaker s conclusion.来源：考试大
Secondly, the speaker assumes that the low crop yields for first-time organic farmers last year are representative of crop yields for organic farmers overall. However, more experienced organic farmers might have had much better crop yields last year. Also, the first-time organic farmers might improve their own crop yields in future years. Moreover, last year s yield may have been unusually low due to poor weather or other factors, and thus not indicative of future yields.来源：考试大
Finally, in asserting that organic farming is financially unwise because it is motivated by environmental instead of economic concerns, the speaker unfairly assumes that a practice cannot be both environmentally and economically beneficial. It is possible that, in the long run, practices that help protect the environment will also result in greater economic benefits. For instance, organic farming methods may better protect soil from depletion of the elements that contribute to healthy crops, providing an economic benefit in the long run.
In conclusion, the speaker s argument is poorly supported and is short-sighted. To better evaluate the argument, we would need more information about the how the survey was conducted, especially about the comparison the survey makes. To strengthen the argument, the speaker must present evidence that last years crop yields from first-time organic farmers are representative of yields among organic farms in general. The author must also provide evidence that environmentally sound practices cannot be economically beneficial as well.