写作提纲：
　　Necessary
　　• 不易被修改，不依赖机器，安全，权威
　　• 传统的健康的方式，老人的习惯
　　Digital book
　　• 节省印刷运输成本，便宜
　　• 环保
　　• 覆盖面积大，传输速度快

　　范文：
　　In the era of information technology, many traditional ways of life have turned into virtual ones, and the advent of electronic-books is a typical example. Young readers no longer restrict their reading to printed materials; instead it is common to see them reading over their mobiles or ipad screens on a bus or in the street. Consequently,some suggest that printed books have become out of date and can be substituted by their counterpart in the electronic version.
　　This sounds reasonable in this modern society. Despite the cut of cost on paper pulp,printing machines and transportation of products, electronic books are much economic. If we take the environmental impact into consideration, e-books would show another advantage over traditional ones which consume abundant plants. In addition, in the globalized world, easy and fast access to knowledge and information becomes increasingly significant, and this requirement can be best met by e-books which spreadfaster and more widely via the internet.
　　However, these advantages of electronic books do not necessarily mean that printed version will be completely replaced soon. Printing is a safe way of saving knowledge because it is not easy to modify the original words once they are printed on paper, which is where the authority of published paper books comes. As a traditional way of life, reading books plays an important part in the elderly population who are used to thumb a book from cover to cover. If printed books are not available any more, they would be the most frustrated group of people. There is the health issue to consider. Reading printed material is healthier than on shining screen for eyesight. Therefore, e-books are not suitable for children.
　　In conclusion, the fact that all writing can be stored electronically does not necessarily suggest the extinction of written books. The two forms of books can co-exist to cater for different groups of people.

　　词汇拓展：
　　单词词义
　　1. substitute 代替
　　2. version版本
　　3. counterpart对应物
　　4. advent到来
　　5. paper pulp纸浆
　　6. take into consideration考虑
　　7. modify 修改
　　8. original 原来的
　　9. authority 权威
　　10. thumb 捻
　　11. frustrate 打击
　　12. extinction 消失
　　13.cater for 满足
　　14.co-exist并存