Noun:

1. counting backward from an arbitrary number to indicate the time remaining before some event (such as launching a space vehicle)

countessn.女伯爵；伯爵夫人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）countable set可数集count of yarn纱线支数counting loop计数循环countingframen.算盘count up mode结算方式counting ring环式计算装置counting vial计数杯counting downn.脉冲分频；倒计时counting grid计数栅counting sort计数分类

1. His heartbeat escalates, like the countdown for death.
   他心跳加快，就象死亡在倒数。
2. I will never employ any device with a digital countdown.
   我将不会使用任何倒数计时用具。