【单选题】Which one is not the reason why Afghanistan government can not eliminate opium quickly?
A.
Opium is closely related with the economy situation of Afghanistan people
B.
It is a hard job which needs time
C.
Afghanistan is not a democratic country
D.
It is a problem left by history and it need more patience
【单选题】在RLC串联电路中,产生串联谐振时,回路的总电抗Z等于()。
【单选题】RLC串联谐振电路中,电阻两端电压____总电压,电感与电容两端电压相等,相位相反,且为总电压的____倍,谐振阻抗表达式为______。
【单选题】图 1-2-16 中, R 2 = R 4 , U ad = 150V , U ce = -70V ,则 AB 间的电压 Uab 为( )
【单选题】Which one is NOT the reason for the airtight security at the data center?
A.
There are dangers posed by hackers.
B.
There is only one Visa center in North America.
C.
There is considerable growth in mobile purchases.
D.
There are a large number of daily transactions processed here.
【单选题】若RLC串联谐振电路中电阻值小于容抗,则电容电压有效值()电源总电压有效值。
【单选题】Among the following which one is not the negative consequence according to the passage?
A.
The kids are emotionally fragile and they can't stand on their own.
B.
They don't know how to make sound decisions.
C.
They aren't equipped to deal with failure and frustration.
D.
They are lucky to have their parents aroun
【简答题】习题1-1 在图 1-1 所示电路中,已知 R 2 = R 4 , U AD = 15V , U CE = 10V ,试用电位差的概念计算 U AB 。