An ebook (also referred to as an electronic book,eBook,or e-book) is a digital version(版本)of a print book that you download and read. But if you want to read an ebook, you must have an Ebook Reader, which is a kind of free software used by your computer. Make sure you have installed the appropriate Reader before you download your ebook from the Internet. The software allows you to turn the words on the screen into the size you like. It also helps you turn pages and change your viewing options(计算机屏幕上的阅读选择). Ebooks are a fun alternative to regular books. You can download them to any computers and create your own library of hundreds of titles. If you load them onto your portable computer,you can take them with you when you travel. Some ebooks are even interactive! Best of all,when you order an ebook,there is no waiting and no shipping charges. The amount of time it takes to download your ebook depends on the speed of your connection and the size of your ebook.