Mains 释义与例句 n. 1. plural of Main 相关短语 mains hum main de fer gas mains water mains fire mains rising mains left mains Davidson's Mains electric mains [电] 总线 water main 总水管 gas main n. 煤气总管 rising main 直上干线 fire main left main electric main 电力干线; 主电线