the acid test a situation or event which finally proves whether something is good or bad, true or false, etc.
☞ The original use of the phrase was to denote a method of testing for gold with nitric acid (gold being resistant to the effects of nitric acid).
1990Which? These deals are designed to encourage impulse buying, so the acid test is whether you would have bought anyway.
英语词组固定搭配大全包含15956条英汉双解词组，基本涵盖了全部常用英文词组、短语的翻译及用法，是英语学习的有利工具。