蓄电池在外电路开路时其容量的无益消耗称为自放电。
参考答案：对
The company designed a new car last month and about 500 cars of this type _____ in the factory next month.[ ]
A. were produced
B. will produce
C. have been produced
D. will be produced
采用两台高频振动棒分层振捣浇筑，利用混凝土换车时进行振捣，振动棒要落点均匀，振点间距不大于（）m。
A、1
B、1.5
C、2
D、3
