An important reason why spam is Rampant: E-mail service is free of charge.

垃圾邮件猖撅的一个重要原因是：电子邮件服务是免费的。

youdao

An important reason why spam is Rampant: E-mail service is free of charge.

垃圾邮件猖撅的一个重要原因是：电子邮件服务是免费的。

youdao