万一
万一万一[wàn yī]1.■ (可能性极小的假设) just in case; if by any chance:可能下雨, 拿把伞吧, 以防万一。It may rain; you'd better take an umbrella just in case.
常用词组1.■ (可能性很小的意外) contingency; eventuality:准备应付一切万一发生的事故be prepared for all contingencies one ten thousandth;防备万一be ready for all eventualities; be prepared for the worst2.■ (极小的一部分) one ten thousandth; a very small percentage