What is certified letter?

什么是挂号信？

youdao

After running through all the reviews and advisory committees that have certified the scanners as safe, the letter concludes.

在查阅了所有相关的资料并走访了证明这种扫描仪安全的相关顾问委员会之后，他们在回信中得出这样的结论。

youdao

Send off your correspondence by certified mail, return receipt requested so you can document when the credit reporting agency received your letter.

欢送你的认证邮件函授、所以你可以请回文件时收到的信用报告机构收到你的来信。

youdao

Many do the minimum, simply sending a certified letter to the address in the tax records.

FORBES: Magazine Article

The following day, all two hundred and seventy-eight employees received a certified letter terminating their employment, effective immediately.

NEWYORKER: Out of the Bronx

Dziekonski got out of his contract eight months into it, after sending Cintas a certified letter of complaint and hearing nothing back.

FORBES: Dirty Laundry