1. Please make sure to obtain proof of posting when mailing important documents.
请确保在寄送重要文件时取得寄送证明。

2. The proof of posting will serve as evidence that the package was sent on time.
寄送证明将作为包裹准时寄出的证据。

3. It is recommended to keep the proof of posting until the recipient confirms receipt.
建议保留寄送证明，直到收件人确认收到。

4. Without proof of posting, it may be difficult to track the whereabouts of the package.
没有寄送证明，可能会难以追踪包裹的去向。

5. The post office provides proof of posting services for an additional fee.
邮局提供额外收费的寄送证明服务。

6. Make sure to check the details on the proof of posting for accuracy before leaving the post office.
在离开邮局前，请确保检查寄送证明上的详细信息是否准确。