由运算放大器组成的比例放大器，可分为（）放大器和（）放大器。
参考答案：反相比例;同相比例
I don't think he could have done such a stupid thing last night,_____? [ ]
A. do I
B. could he
C. did he
D. has he
新录用公务员试用期满后，不合格者可延长试用期。( )
