Pteroceltis pollen percentages are less than 15% in the Pteroceltis forest, and Pteroceltis pollen does not appear when Pteroceltis trees absent.是什么意思_Pteroceltis pollen percentages are less than 15% in the Pteroceltis forest, and Pteroceltis pollen does not appear when Pteroceltis trees absent.在线翻译_英语_读音_用法_例句