英语语法分析

BookCrossing provides an identification number to stick inside the book.

这个网站提供一个识别码，粘在书里。

E-mails are then sent to the BookCrossing to keep them updated about where their books have been found.

然后电子邮件会被发送到这个网站去更新书是在哪里被人找到的。

The purpose of BookCrossing is to track books across the world and to share great literature with strangers.

图书漂流的目的是跟踪图书在世界各地的流动，并且与陌生人分享资源。