1． 上图所示为1990年(每周使用电脑不到2小时)、1995年(每周4小时)、2000年(每周20个小时)某校大学生使用计算机的情况，请描述其变化。
2． 请说明发生这些变化的原因（可从计算机的用途、价格或社会发展等方面加以说明）。
这是一篇图表附提纲式作文，1991年6月的四、六级考试曾经使用过此种命题方式，是四、六级考试历史上第二次使用这种命题方式，虽然考生对此题型不太适应，但却代表了未来四、六级作文命题的发展方向。第一段，利用图表（只在此段中描述图表）描述使用计算机的"情况，突出在使用计算机小时数上的变化。第二段，指出造成这种变化的三个主要原因：首先，社会的发展带来了经济的繁荣；其次，计算机在各个领域的广泛应用；最后，通过调整价格，普通百姓也能买得起计算机了。第三段，计算机在为学生带来益处的同时也造成了一些问题：首先，由于在计算机上花的时间太多而荒废了学业；其次，学生的身心健康受到了一定程度的伤害。
参考范文：
As can be seen from the chart， in 1990， the use of computers was not popular yet， with the university student spending merely an average of one hour on the computer per week。 However， in 1995， the number of hours was quadrupled， climbing up to four hours per week。 In 2000， after a lapse of only five years， it was astonishing to find that the number shot up to nineteen hours every week。
This dramatic change in the average number of hours the student spent on the computer per week took place chiefly for three reasons。 In the first place， as the society developed， national economy became prosperous， bringing about the popularity of computers。 In the second place， the use of computers went far beyond typing words， XXX them indispensable not only to secretaries but also to people engaged in other areas。 Last but not least， prices for computers were reduced， so much so that common people with a modest income could afford them。
It is true that students have benefited from spending more and more time on the computer， but problems have also arisen。 Some students indulge themselves in computer games， refusing to concentrate on their studies， while many other students’ health has been damaged as a result of too much exposure to computers。
