【单选题】用来控制水流只朝一个方向流动,限制水流向相反方向流动,防止突然停电或事故时水倒流的是( )。
【简答题】The delegates decided that _________________ (继续开会,而不是中断会议去吃午餐).
【单选题】Coffee is served during the morning break to delegates attending the product demonstration______ .
A.
Coffee will be available during the meeting if requested.
B.
There is a coffee break for participants during the morning.
C.
Delegates can see a product demonstration while they have coffee.
【单选题】连接储存容器和集流管间的单向阀的流向指示箭头应指向( )。
【简答题】Many proposals were raised by the delegates ,as we expected. _____________________________________________________________________________
【简答题】滑动导柱导套的导向精度比滚动导柱导套的导向精度 ______ 。
【单选题】挤压成形时,金属的一部分流动方向与凸模的运动方向相同,而另一部分的流动方向则相反的称为( )。
【单选题】“ 俗话说‘养儿防老’”这句话中,“养儿防老”的意思是什么?( )