带有稳压放大环节的稳压电源，其放大环节的放大倍数越大，输出电压越稳定。
参考答案：对
They __________ with each other for two years before they got married.
A．had fallen in love
B．got in love
C．had been in love
D．fell in love
下列哪种物质具有过敏毒素作用（）。
A.C3a、C4a、C5a
B.C3b、C4b
C.C1～C9
D.C1q
E.C2b
