Ppb
[化] 十亿分率
🗣️ 情景例句
I only buy used books.
我只买旧书。
Is it too far to walk?
走着去很远吗？
They took with them dogs, rats and plants like the sweet potato,and settled mainly in North Island where the weather was warmer.
他们随身带去了狗、老鼠及像红薯之类的植物，并且大部分定居在气候比较温暖的北岛。