main pipe line的用法和樣例：
例句
- The plumber finds no pipe leaks and suspects a mains leak.
水管工沒(méi)有發(fā)現漏水的水管，懷疑是主管道漏水。 - Bypasses are used in steam service for warming up before the main line is opened and for balancing pressure where the lines are of limited volume.
旁路閥用在蒸汽操作中，用于在主管道開(kāi)啟前對其進(jìn)行預熱以及管道數量有限時(shí)平衡壓力。
