【答案解析】[参考范文]
As is demonstrated in the table, the financial sources of the American students differ from those of their Chinese counterparts. It indicates that all these students are financially supported by their parents, part-time jobs and scholarships. Half of the American students" finance is from their parents, 35% from part-time jobs, and 15% from scholarships. Chinese students, by striking contrast, rely heavily on their parents. On the average: only 5% of their finance comes from taking part-time jobs and another 5% comes from scholarships.
To my best knowledge, a variety of factors are responsible for this phenomenon, as listed below. In the first place, the American students are taught to be financially independent early from childhood, while Chinese parents are inclined to offer financial support for their children"s education throughout the whole process. In the second, American universities offer more chances for the undergraduates to work part-time. Chinese students, however, have fewer part-time job opportunities. In the third, the scholarships offered by American universities are of greater variety and larger amount than those offered by Chinese universities.
Considering all the points discussed above, we may safely draw the conclusion that the trend will continue for long. But under the influence of Western culture and pressure of rising education expenses, a growing number of Chinese students are seeking part-time jobs nowadays. It is an excellent and natural access to both social experience and better financial condition. [解析] 1．主题与类型：图表式作文，题目为大学生经济来源，题目中要求分析中美两国大学生经济来源差异的原因，因此是比较典型的原因分析型。文章写成三个自然段。
2．结构与构思：
第一段：首句从句使用用于图表描述的从句“As is demonstrated in...”，主句需要概括指出两国经济来源是不同的，然后用两三句话展开比较一下两国学生在父母、兼职工作和奖学金方面的经济来源比例上的差异。
第二段：段首句使用用于原因分析的主题句“...a variety of factors are responsible...”，然后从家庭、学校奖学金、兼职机会等方面进行差异原因分析。
第三段：首句使用结论功能句“...we may safely draw the conclusion that...”，可以预测未来发展趋势：客观来看，应该持续一段时间，但中国学生兼职机会和奖学金机会在增多，对父母的依赖可能降低。