there's many a slip twixt cup and lip idiom UK saying (US there's many a slip between the cup and the lip)
杯到嘴边还会失手;世事往往功亏一篑
said to emphasize that many bad things might happen before something is finished
英汉双解词典收录81607条英汉双解翻译词条，基本涵盖了全部常用单词的读音、翻译及用法，是英语学习的有利工具。