While you are at the bookstore， you may be faced with a difficult decision： e﹣books or paper books？ Each one has its advantages and disadvantages． Making the best decision depends on a number of factor （因素）．

An e﹣reader can carry a whole library wherever you go， which is great for travelers or those who always want a choice of reading material Although e﹣readers are convenient， high levels of screen brightness from an electronic device（电子设备） can cause eye problems． A study in the Information Science Research found that young people preferred e﹣readers， like smart phones or iPads． That's why most teenagers are short﹣sighted．

Many book lovers still prefer paper books and value the feeling of them． Paper books are very well designed， they look and smell good， and they carry with them a more human touch． Avid （热衷的）readers prefer reading on paper． Perhaps this is their choice because paper books give them a sense of ownership． It is reported that reading on paper rather than an electronic screen is better for memory and focus． But paper books are heavy and they are not convenient to carry．

Which is your decision， an e﹣book or a paper book？

阅读短文，回答下列问题．（每小题2分，共10分）

（1）How many kinds of books are mentioned in the passage？ 　　

（2）Do young people like e﹣readers better？ 　　

（3）According to the study， why are most teenagers short﹣sighted？ 　　

（4）Which is better for memory and focus， an e﹣book or a paper book？ 　　

（5）What's the main idea of the passage？