When left unattended, torches should be isolated by closing the gas cylinder valves, removing the valve keys and depressurising the hoses.是什么意思_When left unattended, torches should be isolated by closing the gas cylinder valves, removing the valve keys and depressurising the hoses.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句