单词	字音略同
释义	同F
随便看	parts per billion part(s)per billion-- ppb part(s)per billion; ppb parts per billion (ppb) parts per billion {= ppb} parts per billion(ppb) parts per billion-- ppb parts per billion--ppb parts per billion; ppb parts per billion十亿分率 parts per billion， ppb parts per billion｛=ppb｝ part(s)per million parts per million parts per million carbon part(s)per million-- ppm part(s)per million; ppm parts per million (ppm) parts per million {= ppm} parts per million {=ppm} parts per million-- ppm parts per million--ppm parts per million; ppm parts per million 百万分率 parts per million， ppm