【判断题】实地口语导游亦称讲解导游,它包括导游人员在游客旅行,游览途中所做的介绍,交谈和问题解答等导游活动,以及在参观游览途中所做的导游讲解。()p3
【单选题】离心泵启动前需要先向泵内充满被输送的液体,否则将可能发生 现象。
【判断题】离心泵启动前需要向泵充满被输送的液体,否则将可能发生气蚀现象。( )
【单选题】In this factory the machines are not regulated______but are jointly controlled by a central computer system.
【单选题】In this factory the machines are not regulated ______ but are jointly controlled by a central computer system