【简答题】已知电路中,Z1=1.75Ω, Z2=4+j3Ω,Z3=-j3Ω,且Z2与Z3并联后再与Z1相串联;施加在这三个阻抗的总电压为U=220∠0°V。 试求: (1)流过Z1, Z2, Z3的电流相量I1, I2, I3,并画出电压电流的相量图; (2)电路的有功功率、无功功率、视在功率以及功率因数。
【单选题】How many mobile phone users will there be in Australia by the year 2000, according to the passage?
B.
Almost half of the population.
C.
One third of the population.
D.
One fourth of the population.
【多选题】外国旅游团在旅游过程中发生旅游者重大人身伤亡事故在处理中涉及的方面 有 ( ) 。
【多选题】外国旅游团在旅游过程中发生旅游者重大人身伤亡事故,其处理涉及的方面有( )。
【单选题】—_______ are koalas from? —Australia. [ ]
【单选题】How was her flight to Australia?
【单选题】— _____ will your headmaster come back from Australia. —In a few days. [ ]
【多选题】外国旅游团在旅游过程中发生旅游者重大人身伤亡事故,其处理涉及的方面有()。
【单选题】— ______________ do you live? — Australia. [ ]
【多选题】外国旅游团在旅游过程中发生旅游者重大人身伤亡事故在处理中涉及的方面有( )。