The first gas fractionation unit was set up in 1993 with main products propylene, propane and C4 fractionates, propylene tower is the main part.是什么意思_The first gas fractionation unit was set up in 1993 with main products propylene, propane and C4 fractionates, propylene tower is the main part.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句