【简答题】听下面一段材料,回答第1-4题。 1. What season was it? A. Spring. B. Autumn. C. Winter. 2. Why did Mrs. Miller go to buy things on Saturday? A. Because her husband also wanted to do some shopping. B. Because her ...
【简答题】三相异步电动机电源反接制动的特点是制动 ( 快/慢),冲击 ( 大/小)。
【简答题】Fill in the blanks with the words given below. r ight April ong people spring than What and When Is Earth Day? When I proposed to name Earth Day, a global occasion to celebrate the wonder of life on o...
【单选题】儿童不再把规则看成是绝对的、固定不变的东西。他们能部分地根据行为者的意向来判断过错行为的严重程度的阶段是( )
【简答题】听下面一段材料 ,回答第1-3题。 1. Who thought himself to be the bravest? [ ] A. Tom B. David C. Jack 2. What was David doing when they were talking about the courage? [ ] A. Doing nothing B. a fire ...
【简答题】Fill in the blanks with the words given below. right April long people spring than What and When Is Earth Day? When I proposed to name Earth Day, a global occasion to ce...
【简答题】B. Fill in the blanks with the words given below. right April long people spring than What and When Is Earth Day? When I proposed to name Earth Day, a global occasion to...
【多选题】空气进入制冷系统的原因包括( )
A.
制冷系统在投产前或检修时抽真空不彻底,使部分空气留在系统中
B.
充灌制冷剂和冷冻机油时,因操作不慎使空气进入制冷系统
C.
压缩机排气温度过高使部分油和氨分解成不凝性气体存在系统内
D.
低压系统或曲轴箱内压力低于大气压时,空气从阀门、轴封等密封不严处渗入系统
【多选题】关于下图的正确描述有?
B.
红色曲线所对应的制动电阻较小,故制动时的电磁转矩较大,制动时间较短
D.
能耗制动时,为了提供直流磁场,需要从定子绕组中任取两相,且在这两相外面通过一个制动电阻跨接直流电源
【简答题】What thought came into his mind even though he survived the bombing? W hat made him give up the thought?