Reading practice: An e-book, also known as an electronic(电子的) book, is an electronic version (版本) of a print book that you can download (下载) and read. What you need in order to read an e-book is an E-book Reader, which is a kind of free software used by your computer. Make sure you have the proper Reader free software used by your computer. Make sure you have the proper Reader before you download your e-book from the Internet. The software allows you to turn the words on the screen into proper size you like. It also helps you turn pages and change your choice of viewing. E-books are a fun alternative to regular books. You can download them to any computer, including your portable (便携式) computer so you can take them with you when you travel, and create your own library of hundreds of titles. Best of all, when you order an e-book, there is no waiting and no shipping or handling charges. The amount of time it takes to download your e-book depends on the speed of your connection and the size of your e-book.From this passage, we know that an e-book ______.