基本解释[经济学]铲斗控制阀词组短语短语bucket main control valve 铲斗主控制阀backhoe bucket control valve 反铲斗控制阀multipurpose bucket control valve 多用途铲斗控制阀bucket control valve component 铲斗控制阀部件bucket control valve spool 铲斗控制阀滑阀专业释义经济学铲斗控制阀