三相四线制电路无论对称与不对称，都可以用二瓦计法测量三相功率。
参考答案：错
—Who broke the window yesterday?
— ______ Jack ______ Mike. It was Jim.
A．Not only; but also
B．Both; and
C．Either; or
D．Neither; nor
下列气体中（）可以灭火。
A、CO2
B、CO
C、N2
D、Cl2
