最佳答案：on air （无线电）广播的；送风期短语on-air testing 广播测试 ; 传播测试 ; 播送测试on-air light 播发信号灯On-air Test 试播双语例句 1.Pleas
on air （无线电）广播的；送风期短语on-air testing 广播测试 ; 传播测试 ; 播送测试on-air light 播发信号灯On-air Test 试播双语例句
1.Please write about the effect of tree planting on air in a city. 请写写植树对城市空气的作用。
2.But they nevertheless have a big influence on air quality and human health, greenhouse gas emissions and the Earth’s carbon cycle, and biodiversity. 但是依然会对空气质量和人体健康造成巨大影响，加剧温室气体排放和地球碳循环，也对生物多样性不利。
