S

电路如图所示，换路前电路已达到稳态。t=0时S闭合，求S闭合后UL和IL。

已知一节点所带负荷，有功功率为P，视在功率为S，则功率因数角 为（　　）

____________ a marked difference between right and wrong can be very important in one’s career.

——I’m so happy that you could come to English land with us for the holidays. ——_________ . It’s the first time for me to be out of china.

What’s the problem with your bike? ----                          .

A: Is your Web site for teachers or students? B: It’s about 50/50. There is a lot for both, and I try to keep _________.

He is quite sure that it’s _____impossible for him to fulfill the task within two days

He becomes so _____ that he cannot remember his grandson’s name

Who should be responsible ___ the staff’s absenteeism?

----What’s the matter? ----_____________.