如图所示表示一交变电流随时间变化的图象,其中,从t=0开始的每个时间内的图象均为半个周期的正弦曲线。求此交变电流的有效值
A.3A
B.A
C.A
D.A
答案:C
The doctor had almost lost hope at one point, but the patient finally ________ .[ ]
A.pulled through
B.pulled out
C.pulled up
D.pulled over
分鱼、禽类菜肴时用()相互配合操作。
A.餐刀
B.筷子
C.餐叉
D.餐勺