三图一表--柱状图（Bar Graph）、线形图(Line Graph)、饼状图(Pie Graph)、表格(Table)Paragraph I:（1）描述图表：趋势描写；
（2）描述图表：必要数据支持（细节性）.
Paragraph II:（1）提出自己理由和观点；
（2）细节性分论点（支持自己观点）.
Paragraph III:（1）预测未来和提出解决方法；
（2）总结全文和表达作者自己观点.
下面的例子对你有帮助的
As is shown by the bar graph, the average number of hours a student in a certain university spends on the computer per week increased dramatically over the period from 1990 to 2000. In 1990, it was less than two hours. And in 1995, it hit four hours. And in 2000, the number soared to nearly twenty hours, which is over ten times than that of 1990.
第一段还有一种写法：
In 1990, the number was less than 2 hours, while the figure hit 4 hours（或者这样写：while in 1995, ）as compared with that of 1990, it had almost doubled. And what impress us most is that the figure soared to ……, which……
Obviously computers are becoming increasingly popular for males and for females. A multitude of factors could account for the rise. In the first place, computers facilitate us in more aspects of life. Also, the rapid development of the internet enlarges our demands for using computers. We can easily contact friends in remote places through the internet. In the second place, the prices of computers are getting lower and lower, which enable more students to purchase them.
However, there still exist some problems, such as, poor quality, out-of-date designs and so on. And how to balance the time between using computers an studying is also a serious problem. Anyhow, we will benefit a lot from computers as long as we use them properly.