mail delivery subsystem是什么意思啊?

Mail Delivery mail delivery system是什么意思 e-mail-delivery是什么意思 mail delivery subsystem是什么意思啊? Mail delivery failed:returning message to sender This message was created automatically by mail delivery software (Exim). Delivery Delivery 我用Yahoo发邮件的时候受到一封这样的信件.信头是这样的Delivery Notification:Delivery has failedInternet Mail Delivery People call this mail service Rural Free Delivery.(变为被动语态) 发了邮件后收到Mail Delivery System发过来的英文邮件,发了邮件后收到Mail Delivery System发过来的英文邮件Mail Delivery System<MAILER-DAEMON@mx2-198.sinamail.sina.com.cn>This is the mail system at host mx2-198.sin 24.Sending ____ special delivery costs about 15 times as much as sending it regular delivery.A.a mail B.mails C.a piece of mail D.pieces of mailmail不可数吗? mail 英语翻译A:what delivery arrangements did you make for the file?Q:I sent it by express mail. 英语翻译1：Delivery Status Notification (Delay) This is an automatically generated Delivery Status Notification.Unable to deliver message to the following recipients,due to being unable to connect successfully to the destination mail server.2： Transcripts can be submitted via regular or express mail delivery; some applicants send in a CV and a list of publications along with the transcript.This is optional. This message was created automatically by mail delivery software.不用给我翻译,这是怎么回事?我是网易用户,这种情况应该怎么解决啊?急救! 英语翻译Mail Delivery System》Undelivered Mail Returned to SenderThis is the mail system at host mail.w-sky.com.I'm sorry to have to inform you that your message could not be delivered to one or more recipients.It's attached below.For further as