对空射击

fire into the sky

对空战斗

air warfare

对空防御

air defence

对空联络

ground-to-air communications

空对地导弹

air-to-surface missile

空对空导弹

air-to-air missile

空箱子

empty box

空的火车

empty train

空的卡车

empty truck

空子弹

blanks

空衣兜

empty pockets

空签

blank

空弹射击

shoot blanks

卡车放空。

The truck has been unloaded.

空放里程

unloaded mileage

屋子里空无一人。

There's not a single soul in the room.

空费气力

expend one's strength for nothing

空忙一场

make a fruitless effort

空吹一通

prattle away about nothing

空放了一枪

fired and missed

用不着空跑

pointless journey

你空欢喜什么。

Don't count your chickens before they hatch.