| 词源 |
acid test. This expression dates back to frontier days in America, when peddlers determined the gold content of ob- jects by scratching them and applying nitric acid. Since gold, which is chemically inactive, resists acids that corrode other metals, the (nitric) acid test distinguished it from copper, iron, or similar substances someone might be trying to palm off on the peddlers. People were so dishonest, or peddlers so para- noid, that the term quickly became part of the language, com- ing to mean a severe test of reliability. |