生产中发生堵溜子时可使提升机(),或()。
参考答案:返料;混料
如图,A、B为两等量异号点电荷,dbe为中垂线,ab=bc、be=db,则 ( )
A.a点与c点的电场强度相同 B.a点与c点的电势相同
C.a、b间电势差与b、c间电势差相同 D.在d点释放一电荷,它将在中垂线上d、e之间来回运动
—Can you guess ______ the new schoolbag yesterday?
—Sorry, I’ve no idea.
A.how much did he pay for
B.how much he spent
C.how much he paid for
D.how much did he spend