A: meal
B: Internet
C: cable TV
D: electricity
举一反三
- They have a [u] [/u] when the electricity fails. A: generous B: generator C: dangerous
- They have a [u] [/u] when the electricity fails. A: generous B: generator C: dangerous
- 在三相交流电路中,三相相电压分别是uA=UmsinωtV,uB=Umsin(ωt-120°)V,uC=Umsin(ωt+120°)V,若u=uB+uC,则u为 A: u=2UmsinωtV B: u=UmsinωtV C: u=Umsin(ωt-180°)V D: u=2Umsin(ωt+180°)V
- 我国照明电路使用交流电,电压有效值是220V,频率是50Hz,这交流电的电压表达式是()。 A: u=220sin50tV B: u=220sin110πtV C: u=311sin50tV D: u=311sin110πtV
- When you rent a flat, you will need to pay for gas and electricity, water, broadband, and digital TV on top of your _______. A: contract B: rent C: payment D: bill
内容
- 0
They will [u] [/u] on a meal fit for a king. A: fever B: feast C: feasible 未知类型:{'label': 'questionDesc', 'content': '请选择正确答案', 'isMemberControl': 0, 'type': 181}
- 1
已知,交流电压u1=10sin100πtV,u2=10sin(100πt-60°)V。则u=u1-u2的解析式为()。 A: u=10sin(100πt+60°)V B: u=10sin(100πt-60°)V C: u=8sin(100πt+30°)V D: u=8sin(100πt-30°)V
- 2
已知,交流电压U1=10sin100πtV,U2=10sin(100πt-60°)V,则u=u1-u2的解析式为() A: U=10sin(100πt+60°)V B: U=10sin(100πt-60°)V C: U=8sin(100πt+30°)V D: U=8sin(100πt-30°)V
- 3
某正弦电压有效值为220V,频率为50Hz,在t=0时,u(0)=220V,则该正弦电压表达式为()。(A)u=380sinl00πtV(B)u=311sin(100πt+45°)V(C)u=220sin(100πt+90°)V(D)u=-311sin(100πt+45°)V
- 4
有如下程序: #include using namespace std; class TV{ public: TV(int s=41):size(s) { } TV(const TV &r):size(r.size) { } ~TV() { } private: int size; }; TV fun(TV &u) { TV t=u; return t; } int main() { TV x,y; x=fun(y); return 0; }则 TV 类的复制构造函数被调用的次数是 A: 1次 B: 2次 C: 3次 D: 4次