one swallow doesn't make a summer idiom saying
独燕不成夏（指一件好事的发生并不意味着整体情况会好转）
used to say that because one good thing has happened, it is not therefore certain that a situation is going to improve
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。