Gōng / zuò / rén / yuán / jiǎn / chá / le / yóu / chuō / què / rèn / zhè / fēng / xìn / shì / zuó / tiān / jì / chū / de

工作人员检查了邮戳，确认这封信是昨天寄出的。

The staff checked the postmark and confirmed that the letter had been sent yesterday.