air /ɛə/ I. n.［u］1.空气；天空：breathe fresh/pure air 呼吸新鲜空气；air defence 防空；air corridor 空中走廊 Man couldn’t live without air. 没有空气人就无法生活。2.用于习语 by air 乘飞机；航空寄信：travel by air 乘飞机旅行；send the letter by air寄航空信 in the air 空中；显而易见的；流行中的：Many birds are flying in the air.许多鸟儿在空中飞翔。I smell violence in the air.我明显地闻到了暴力的气息。off the air 停播：As soon as the war started, any broadcasts with a military theme were taken off the air.战争一开始，有关军事题材的一切内容就停播了。on (the) air播放：The radio station is on air from 6.00 a.m. 电台从上午六点开播。The interview will be on the air tomorrow.会见情况将在明天广播。 up in the air 悬着，没有决定：I may be moving to New Zealand, but it’s still up in the air.可能搬到新西兰去，但此事还没有决定。‖II.vt. 使通风：We air the room by opening the windows. 我们打开窗户给房间通风。