【单选题】在电动机起动或短时过载时,热继电器不会动作,这可避免电动机的不必要停车,这种“热惯性”使热继电器不能做( )保护。
【简答题】During last summer vocation, I decided to find a part-time job. During last summer vocation, I decided that ______.
【简答题】During last summer vocation, I decided to find a part-lime job. During last summer vocation, I decided that ______ .
【多选题】下列关于液压泵的分类正确的是()
C.
按泵的输入的流量能否调节可分为定量泵和变量泵
D.
按泵的额定压力的高低可分为低压泵、中压泵和高压泵
【单选题】人们常按液压泵额定压力的大小来进行分类,柱塞泵属于( )油泵。
【单选题】I_____at a summer camp in New York last summer and enjoyed supervising a group of four children.
【判断题】热继电器在电路中可以做瞬时过载保护和短路保护。
【单选题】I like to play in the wind in . [ ]
【判断题】当昆虫饥饿和脱皮时,外表皮可被消化、吸收,因而外表皮具有贮备营养成分的功能