管理具有二重性，即同时具有______。
A．阶级属性和社会属性B．自然属性和阶级属性 C．自然属性和社会属性 D．市场属性和生产属性
参考答案：C
By the time I got to school, I realized that I ______ my pen at home. [ ]
A. have forgotten
B. have left
C. had forgotten
D. had left
某投资项目年营业收入140万元，年付现成本70万元，年折旧额30万元，所得税税率 40%，则该项目年经营净现金流量为( )万元。
A．46
B．54
C．58
D．72
