• 倒数

countingn.计算countv.计算；视为；依赖；重要，有价值n.计数；总数n.伯爵（欧洲国家的贵族头衔）count up the figures把数字加起来count on the fingers屈指计算counting house books商号帐簿counted ballot paper已点选票counting of carriers计算小车Count of Steel-Bar棒材计数counting flow length流长计数count one's chickens数鸡count of clear-sky晴天日数count rate indicator计数率指示器

1. The controllers counted down to blast-off.
   控制器倒读数至发射时间。