单选题
（1）合上电力开关QA0后，按下启动按钮SF2，电动机为（ ）。
Y形降压启动
Δ形降压启动
Δ形全压运行
电机无法启动
单选题
（2）当电机启动后，正常运行时间T后，电动机为（ ）。
Y形降压启动
Δ形降压启动
Δ形全压运行
停止运行
单选题
（3）电机正常运行后，按下停止按钮SF1后，电动机为（ ）。
Y形降压运行
Δ形降压运行
Δ形全压运行
停止运行
单选题
（4）主电路中的电气图形BB是（ ），用于实现过载保护。
指示灯
熔断器
接触器线圈
热继电器
填空题
大多数人都希望伴侣有以下的特点：热情和忠诚、吸引力和活力、社会地位和资源这些特点，但它们并非 1 。
填空题
Lisa is analyzing the questionnaire about online shopping.
Lily: Hi,Lisa. Pretty busy? Right?
Lisa: Yeah,I'm collecting data from the questionnaires for the online shoppers on the 1 .
Lily: Really? Sounds interesting.
Lisa: Well,the results are quite 2 . What do you think are the most popular things people buy online?
Lily: Definitely,clothes.
Lisa: No,at first I thought so too,but the results show that I'm wrong.
Lily: How could that be? If the most popular thing being sold online is not clothes,then what is it?
Lisa: Don't feel surprised. 3 the survey,online courses 4 the first place,especially the courses for accounting and languages.
Lily: Really? It's unbelievable. What's next? It should be the clothes or snacks,right?
Lisa: You are wrong again,the results shocked me too. Following online courses,health products 5 the second place.
Lily: That really surprised me,too. You just taught me a lesson and 6 my understanding about online shopping.
Lisa: Have a seat,and let me show you some more unexpected results.
Lily: OK! I'm really 7 about it.
填空题
PLC控制的等效电路由 1 、 2 和输出部分组成。
填空题
模块式结构PLC是将 1 单元、 2 单元、智能I/O单元、通信单元、电源做成相应的独立模块，各个模块可以插装在 3 上，模块之间通过底板上的总线相互联系。
填空题
PLC系统的存储器主要用于存放系统程序、 1 及 2 。
填空题
PLC具有 1 转换和 2 转换功能，完成对模拟量的控制与调节。