根据给出的提纲写作文与段首句作文有很大的相似性。事实上，根据每段的提纲，就可以得出每段的main idea，再根据main idea写出每段段首的topic sentence，由此就可以按照写段首句作文的方法来写提纲作文了。
Sports benefit us in many respects.(根据main idea 写出topic sentence。) When taking part in sports, we get the chance to train almost all parts of our bodies. There is no doubt that proper sports activities keep our physical fitness. Furthermore, sports can enrich our life and maintain our psychological health. Through participation, everyone can learn that on the playground he not only struggles for himself but also fights for his team. Sports teach us about consideration, cooperation and optimism to failure.(关键词的并列往往可以给阅卷人留下深刻的印象。)
But sports can do some harm to those who cannot plan their activities properly. Too hard training may hurt their bodies, exhaust their vigor, and even cause them to become sick.
In general, I love sports. I enjoy sports. For sports not only help me to live a well-balanced life, but also provide me with opportunities to get closer to nature. Sports add happiness to my everyday life when I perform in a decent way.(decent这个词用得恰到好处，在这里也正是“恰到好处”的意思。)
Advertisement can be a service to people. First, it is informative, and can help people buy and sell goods. Second, it can widen people's knowledge, and make people more experienced. Lastly, people can enjoy themselves through those programs which advertisements have been put into.(分条举例说明广告的益处。)
Some advertisements, however, are not very useful to people, sometimes even harmful. An advertisement like this, for example, may put thousands of women and girls into trouble. "Disillusioned with life, love, marriage? You need help. Phone me." And the Savior gives his phone number to his sheep.
In modern times, many advertisements are subjective rather than objective, persuasive rather than informative.(说理客观。) The only purpose of these advertisements is to persuade people to buy their poorly made products. Therefore, it is wise for people to make sure the advertisements are telling the truth.(根据提纲中第三段的主旨来写如何正确利用广告。)