运算放大器的输出信号与两个输入端的信号电压差（）。
A.相等
B.对称
C.成正比
D.成反比
参考答案：C
Only lately about the dark secrets behind the seemingly-happy marriage of the golf star Tiger Woods.
A．the public have known
B．were the public known
C．have the public known
D．the public knew
常见的断路器触头分为（）、（）、楔入式、滑动式触头。
