noun 下载 🔗分享 纳克,毫微克 A unit of mass equal to 0.000 000 001 grams. Symbol: ng Examples : "The lab test detected only a few nanograms of the pesticide in the apple. " 实验室检测出苹果中只含有几纳克的杀虫剂。 mass unit science 与AI对话词汇游戏阅读练习