一旦

一旦 [yī dàn]

1. ■ （一天之间） in a single day; in a very short time:

毁于一旦 be destroyed in one day;

溃于一旦 collapse overnight

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常用词组

1. ■ （不确定的时间） once; in case; now that:

一旦时机成熟 Once the time is ripe...;

一旦失去信心， 就甭想做好工作。 If [When] one loses confidence, he can never expect to do his work well.

一旦抓住了主要矛盾， 一切问题就迎刃而解。 Once the principal contradiction is grasped, all problems will be readily solved.