Ppbv
abbr. parts per billion by volume 十亿分体积比
🗣️ 情景例句
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你好吗？
To speed-read
速读
they would devour all our crops and kill our flocks and herds, if it were not for the protection we get from insect-eating animals.
昆虫会吞食我们的全部庄稼，杀死我们的成群的牛羊。