the operative word idiom
关键词;最重要的词
the most important word in a phrase, which explains the truth of a situation
He was a painter - "was" being the operative word, since he died last week. 他曾经是位画家——“曾经”是关键词，因为他上周去世了。
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。