象许多网虫一样，我的一位朋友经不住网上各种“宝藏”的吸引，到处去申请、注册或订阅，于是邮箱里的信件就日渐增多，各种垃圾邮件也随之而来。虽然现在有一些提供邮件过滤的软件，能够阻挡部分垃圾邮件，但是它们大多必须预先设置需要过滤的邮件种类，而实际上很难预先知道 Like many web worms, a friend of mine can not apply, register, or subscribe to various “treasures” on the Internet. As a result, the number of letters in the mailbox is on the rise, and various types of spam are also coming. Although there are some software that provide mail filtering, which can block some spam, most of them must pre-set the type of mail to be filtered, but it is actually difficult to know in advance