When asked about this major traffic accident, the policeman said it should not have _________ if the driver hadn’t been speeding.

A．come out

B．come about

C．come across

D．happen

减少装置电耗，错误的方法有（）。

A、汽轮机尽量多用汽

B、气压机组脱电机运行

C、烟机进口蝶阀尽量开大

D、保持烟机长周期运行