the then emerging是什么意思

双语例句

(1)The J-10 programme began in the mid-1980s as an air-superiority fighter to rival the then emerging Western and Soviet third-generation fighters such as the F-16 and MiG-29.

开始于1980年代中期的J-10项目被视为一种空优型战斗机，以此对抗逐渐浮现的西方和苏联第三代战斗机如F-16和米格-29的威胁。