—Sorry,I have no time to help you cook.I have a lot of work to do.
—________You have been playing computer games all morning.
A:I'm stuck.
B:Oh,don't mention it.
C:So what?
D:Oh,come on!
对待文化差异的正确态度是( )
如图所示,在“测量滑轮组机械效率”的实验中,物体重6N.沿竖直方向匀速拉动弹簧测力计,物体上升高度为10cm,此时弹簧测力计的示数为____N,滑轮组的机械效率是____.