参考答案：

An official investigation reveals that the nearsighted rate of the Chinese students has occupied the second place in the world. As the chart indicates, nearly one third of primary school pupils, about F0% of junior middle school students, GG.C% high school students and H0% university students suffer from shortsightedness.

Many factors have led to the high incidence of nearsightedness among young students. Excessive schoolwork and frequent contact with electronic screens are the main causes. The eyes need rest and proper care. But students are so fully occupied with all kinds of courses, both necessary ones and unnecessary ones, that their eyes are over burdened. Therefore, nearsightedness is inevitable. Related to this is the extreme inactivity of the teenagers. They cannot afford to spare time during the day to do exercises.

The solution to this problem is obvious. Reduce the class hours and increase the time for sports. However, it is easier said than done. Although the children may be willing to accept this, the parents and teachers are reluctant to do so. They believe that the students must learn as much as possible to ensure a bright future.

解析：

[提示] 先梳理图表所传递的信息，即我国学生近视率高发的现象：近视发病率随着学龄的增长而增长，大学生中的近视率已经高达80%。其实，这个问题的严重性人所共知。几十年前，小学生中少有戴眼镜者，但现在，戴眼镜的小学生比比皆是。亦有报道说．近视发病率有逐年低龄化的趋势。

在充分叙述现象及其严重性后，可以论述这一现象的危害，也可以分析这一现象的成因。学生的高近视率从一个方面反映了我国青少年身体健康存在问题，这有悖于教育关注人的全面发展的宗旨，也与我们努力塑造的体育大国的形象不相匹配。同时，视力差也会限制青少年未来的专业发展，尤其会对我国未来自然科学领域的发展带来不利因素。从成因的角度展开话题，可考虑到教育领域的问题，也可以把重点放在重金牌的体育发展没有给广大青少年带来强健体魄等问题。既可以只写危害或成因，也可以两者兼顾，各成一段，最后以补救建议收尾。