词典释义：
释义
n.
an act of counting numerals in reverse order to zero, especially to time the last seconds before the launching of a rocket or missile
（尤指火箭或导弹发射前的）倒计数，倒读数
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the missiles' launch crews would begin their final countdown .导弹发射的全体人员将开始最后的倒计数了。
(常作
（重大事件发生前的）最后时刻；最后时刻的工作
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it is hard to imagine the countdown to war continuing without an intensification of diplomacy .战争一触即发，而外交努力却没有加强，这是难以想像的。
a digital display that counts down
倒计时显示器。
