看完赛题，一起来解析下两位参赛选手的作文：（蓝色是fact，红色是opinion）

选手一：

Graph 1 illustrates the number of mobile Internet users and annual growth rates during the period of 2011 to 2017 and graph 2 shows the market size for mobile Internet reading products and annual growth rates of that in China from 2011 to 2017.

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Combining the two graphs, we can conclude that as number of mobile Internet users explodes, the market size for mobile Internet reading devices keeps expanding. However, the annual growth rates of mobile Internet reading products’ market size fluctuate, especially between 2012 and 2014, though the annual growth rates of the number of mobile Internet users keeps decreasing. 

（所选取例子为学生原始作文）

分析：作为范例作文，可以看出，事实占据了较大篇幅，仅有的一句观点也是为事实服务，是基于事实的客观总结，写作目的自始至终都是在说明和解释。

选手二：

The mobile Internet has been more and more popular in China in the recent 5 years. China is becoming one of the biggest Internet nations in the world. There is data that shows us how the trend grows and what the mobile Internet in China will be like in the near future (2016 and 2017)

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The magnificent growth in both mobile Internet users and its market size shows the importance of the Internet to this generation in China. We have evidence to believe that as long as the Internet keep developing, the number of Chinese users and the market size will never stop growing to a new stage. 

（所选取例子为学生原始作文）

分析：这篇文章中观点占据了大部分篇幅，超出了图表本身给的数据，并不是客观的解释，无法达到说明文的写作目的，也会给读者造成困惑。这些观点既不是客观总结，也无法在文中找到核心论点，最后使文章变成一篇写作目的不明确的“四不像”。

总结：“Fact”与“Opinion”都可用在说明文中，不过要牢记，在说明文中，观点是基于事实的客观总结。说明文的交流目的始终是解释、说明一个Point，而不是论证，这个Point可以是“Fact”也可以是“Opinion”。说明文中的“Fact”要准确、详实、高度相关。无论是“Fact”还是“Opinion”，表述语气都以客观、中立为特点，并用以说明。