parts-per-billionCOCA²⁴³²⁴⁷BNC²³⁶²¹³⁺¹Economist⁵³⁵⁸¹⁺¹ 基本例句 un.十亿分之几；🌏十亿分率范围内；十亿分之几数量级 Researchers can still account for nearly every drop of water and watt of sunlight, track parts-per-billion flows of carbon and oxygen, and monitor every organism. 研究人员依然能够分析几乎每一滴水、每一瓦特阳光，能够追踪碳氧流量以及监测每一种生物体。 yeeyan