any substance that lessens the purity or effectiveness of a substance
双语例句
Because of morphological changes and adulterants sold of Pinellia ternata in the market, it is becoming more and more difficult to identify various types of Pinellia ternata. 摘要随着市场上半夏混淆品的盛行及半夏本身形态学的某些改变，使传统的形态学鉴别方法难度增加，必须结合其他方法才能准确鉴定。
