| 释义 |
第一级 Dì Yī Jí
基本例句
first stepprimaryfirst-order繁体第一級那是第一级的邮件，收到时却处于第二级状态。It arrived by first-class mail in second-class condition.
第一级运载火箭是用来发射火箭的，进入高层大气後即抛掉。The first-stage vehicle is used to launch the rocket and is then jettisoned in the upper atmosphere. |