项目的财务分析站在______考察项目的经济效益。
A．项目投资者角度
B．项目经营者角度
C．项目未来的债权人角度
D．以上全选
参考答案：D
The expert offered us another piece of advice,_____of great help to our program.
A．I think it is
B．I think which is
C．which I think it is
D．which I think is
工频交流电一般为（）。
A、50Hz
B、60HZ
C、65Hz
D、80Hz
