你能把那份文件作为电子邮件附件发过来吗？

Could you please send the document as an email ___attachment?

这个文件太大，无法作为单个附件发送。

The file was too large to send as a single ___attachment.

别忘了将合同作为附件附上。

Don't forget to include the contract as an ___attachment.