The principle and practices on the up-ward flow of fecal substances and long distance transportation in the vacuum sewer system (VSS) are discussed.是什么意思_The principle and practices on the up-ward flow of fecal substances and long distance transportation in the vacuum sewer system (VSS) are discussed.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句