一级的

• firstlevel
• primary
• first-degree

例句

1. 那是第一级的邮件，收到时却处于第二级的状态。
   It arrive by first-class mail in second-class condition.
2. 那是第一级的邮件，收到时却处于第二级状态。
   It arrived by first-class mail in second-class condition.
3. 必须具备大专院校的学位才能从事这一级的工作。
   A degree is prerequisite for employment at this level.