【简答题】一低压照明系统,系统电源电压及电流瞬时值表达式分别为 (314t+30°)V, (314t-30°)A,问: (1)系统cosα为多大? (2)系统的有功功率户、无功功率Q、视在功率S各为多大? (3)负载的性质? (4)若要提高功率因数到0.95,需要多大Qc?
【单选题】How can we finish the work in the( )of any other helpers?
【单选题】–How soon can you finish the work? --We can finish it in 20 minutes if we have one more person ________ us.
【简答题】毕业设计论文环节的整个过程包括:选题、布置任务书、实习、文献查阅、开题、 、 和 。
【单选题】— How can we finish the task in such a short time? — Don't be worried. There ______ willing helpers. [ ]
【单选题】It remains a question_______we can finish the project in such a short time.