The post office has promised to resume first class mail delivery to the area on Friday.

邮局已承诺在星期五恢复该地区第一类邮件的递送。

《柯林斯英汉双解大词典》

A: I want to send this package by first class mail.

A：我想用第一类邮件寄这个包裹。

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Written materials are supposed to be sent by the more expensive first class mail.

书写的东西都作为收费较高的第一类邮件寄发。

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DVDs are delivered free to subscribers by first class mail, with a postage-paid return envelope, from 58 distribution centers.

ENGADGET: Netflix notches 2 billionth delivery with a Blu-ray disc HD

The news from the United States Postal Service that they will stop delivering first class mail on Saturdays starting this August.

FORBES: How The USPS Decision To Stop Saturday Mail Delivery Will Affect Marketers

Every time someone decides to stop receiving a paper bill, 24 pieces of First Class mail per year disappear forever (the bill, and the payment, each 12 times per year).

FORBES: First Class Mail is Doomed. Get Over it.