国际民航运输协会要求各个地区每两年举行一次技术性会议。

Iata requires that, at two yearly intervals, technical conferences are held in each of the regions.

youdao

国际民航运输协会要求各个地区每两年举行一次技术性会议。

Iata requires that, at two yearly intervals, technical conferences are held in each of the regions.

youdao