国民经济核算体系的组成要素包括基本概念和______。
A.统计分类标准
B.核算原则和方法
C.核算标准
D.指标体系
E.基本表式和账户
参考答案:A,B,E
He did not regret saying what he did but felt that he _____ it differently. [ ]
A. could express
B. would express
C. could have expressed
D. must have expressed
要求提高放大电路的带负载能力,同时减小对信号源索取的电流,应引入()
A.电压串联负反馈
B.电压并联负反馈
C.电流串联负反馈
D.电流并联负反馈