【案例】

 31. The following appeared as part of the business plan of an investment and financial consulting firm:

 "Studies suggest that an average coffee drinker's consumption of coffee increases with age, from age 10 through age 60. Even after age 60, coffee consumption remains high. The average cola drinker's consumption of cola, however, declines with increasing age. Both of these trends have remained stable for the past 40 years. Given that the number of older adults will significantly increase as the population ages over the next 20 years, it follows that the demand for coffee will increase and the demand for cola will decrease during this period. We should, therefore, consider transferring our investments from Cola Loca to Early Bird Coffee."

Discuss how well reasoned ... etc.

【逻辑错误】

 典型的单argument题型，我们可以按照逻辑错误的个数来分段。

1：忽略其他变量/没有控制变量；

2：证据不足；

3：“井底之蛙”。

【范文】

 This business plan affords an advice that the investment and financial consulting firm should transfer their investments from Cola Loca to Early Bird coffee. This advice seems grounded as（开头段写半句让步一下的好处就是可以自然引出案例中的事实内容） the number of elders is predicted to have a significant climb in 20 years and simultaneously individuals (aged from 10 to 60) tend to drink more coffee when they age. However, based on three suspicious assumptions, this argument is less likely to be persuasive (开头段简单直接给出逻辑错误的个数).

The first assumption is that the supply of coffee and cola will be the same in the next twenty years as currently （忽略其他变量—要想消耗量增加或者减少，未来的供应量要先探讨）. The thing is whether the consumption of coffee and cola is likely to increase and decrease respectively in the future as estimated hinges on a host of factors. Whatever it is much higher costs on raw materials, a switch from an indulgent lifestyle to a restrained one or brain drains in coffee and cola manufacturing, the amount of coffee and cola available may be affected（细节补充，注意表达的概括性和清晰度）. Thus, possible as the indication correlating age with preference for coffee and cola is in these studies, it is dubious the consumption of coffee and cola is as assumed in the future when supplies of them are not necessarily to be guaranteed （四句话完成的一个段落，段尾总结逻辑错误的核心内容）.

The second assumption is that the number of aged population increases evenly in the next two decades (证据不足，很难说明人口变化在未来). Yet, it is of high possibility that the number of the elderly boosts in the first 5 years but after that it climbs sluggishly. As a result, the investment plan only helps the investors make fortunes in the early years but fail to ensure constant profits. This scenario could be even worse when the explosion of aged population ensues in the last five years of the two decades since the financial loss at the initial phase of an investment period may frustrate the investors and end their further put of funds (分析逻辑错误的细节注意体现递进的层次，体现思维深度). The recommendation of investing coffee rather than cola is ill-founded when a promising market for coffee fails to be verified (同样是四句话完成的一个段落，注意本段的层次设计).

Finally, it is assumed that there are two types of drinks to invest: coffee and cola. They are, however, only segmentary alternatives available in market （没有考虑到市场上可投资的饮品还有很多种）. Other types of drinks such as juice or tea, if more well-accepted in daily dietary and social contacts, deserve more investment. How could this firm change its mind from investing coffee to cola without detecting these possibilities? （问句也可以用来写逻辑提升的部分）Even though these alternatives aforementioned do not serve as dominant drinks as coffee does, funding Early Bird Coffee is not necessarily the best choice—what if there is a more profitable and cost-efficient coffee brand?（继续写问句来补充细节） This argument is prone to be untenable when there lacks detection on others drinks or coffee brands.

Conclusion

(略)

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