Any of various viscous substances that are exuded by certain plants and trees and dry into water-soluble, noncrystalline, brittle solids.是什么意思_Any of various viscous substances that are exuded by certain plants and trees and dry into water-soluble, noncrystalline, brittle solids.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句