基本单元是PLC系统的最小硬件配置,它包括电源和()
A、CPU
B、存贮器
C、I/0单元
D、程序
参考答案:A, B, C
第二节 根据对话内容,从对话后的选项中选出能填入空白处的最佳选项。
—Hello , may I speak to Dr.Firth?
—__61___ .Dr Firth has just gone to a meeting .
—___62___.
—It’ll be my pleasure.
—I’m Dick .Please tell him to call me when he comes back.I want to know whether my daughter is quite well.
—__63___.Your daughter is quite well now.
—Really?__64___
—-Your daughter Carol, Dad!
—Oh , my dear! __65___
—Yes , I hope I can go back tomorrow.
A.Are you all right now?
B.I’m afraid you can’t
C.Who are you then?
D.That’s great.E.Don’t worry .
F.Would you mind giving him a message?
G.You’re welcome.
如图所示的四种情景中,属于重力势能转化为动能的是
A.(a)图运动员拉开弓,将箭射出
B.(b)图跳水运动员从空中下落
C.(c)图运动员骑自行车冲向坡顶
D.(d)图跳伞运动员匀速下落