合同转让是指（）
A.合同的标的发生变化
B.合同的主体发生变化
C.合同标的物的品质发生变化
D.合同的价款发生变化
参考答案：B
. The millions of calculations involved, had they been done by hand, _____ all practical value by the time they were finished.
A．could lose
B．would have lost
C．might lose
D．ought to have lost
我国规定的电力网标准电压等级10、35、110、220、500kV是指（）。
A.相电压
B.线电压
C.直流电压
D.正常运行时对地电压
