柯林斯词典litmus /ˈlɪtməs/ 1. N a soluble powder obtained from certain lichens. It turns red under acid conditions and blue under basic conditions and is used as an indicator 石蕊 返回 litmus剑桥词典a powder that is turned red by acid and blue by alkali 石蕊 litmus paper 石蕊试纸 a litmus test 石蕊测试 返回 litmus