CAUTION - Do not install a strainer ahead of the backflow preventer on seldom-used, emergency water lines (i.e. fire sprinkler lines).是什么意思_CAUTION - Do not install a strainer ahead of the backflow preventer on seldom-used, emergency water lines (i.e. fire sprinkler lines).在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句