first-class mail造句

1、And it gets worse. By 2020, first-class mail volume is expected to drop by half.
2020年的情况会更糟，一类邮件数量预计将减少一半。

2、It arrived by first-class mail in second-class condition.
那是第一级的邮件，收到时却处于第二级状态。

3、And it gets worse.By 2020, first-class mail volume is expected to drop by half.
2020年的情况会更糟，一类邮件数量预计将减少一半。