noun🔗Share劣质合金，贱金属合金 Any of several alloys of precious metals and base metals that are used (where legal) to make coins, medals etc."The ancient Roman coins, made of billon, have tarnished over centuries, revealing the mix of silver and copper. "这些古罗马硬币由贱金属合金制成，历经数个世纪已经变得黯淡无光，显露出其中银和铜的混合物。materialvalueeconomyChat with AIVocabulary GamePractice Reading
