Probably you have seen someone reading a book on an electronic reading device. Over the past few years, these small computers have become more popular. For that reason, more companies that make   小题1:  paper books are now making electronic books (e-books). Most e-books are the same as paper books,   小题2:  people download a file into a reading device rather than   小题3:  the paper book. This way they can   小题4:  many books.

Books companies are adding special features   小题5:  some e-books. These extra features might include sound files, picture files, or video files. When the readers click on these files they learn more about the book, the story, or the writer.

The latest electronic readers are smaller and   小题6: , but they are also much more powerful. They can store much more information, so writers and book companies can do more with   小题7:  e-books. They do not want to just add files to   小题8:  completed book. They are making the sound, picture, and video files part of the story. Readers need these files to understand the whole story. Readers can   小题9:  change the story.

Readers already have a lot of books to   小题10:  from. If they can change the way stories end, they will have more choices!

什么是图像子采样？各种子采样的有何区别？