If you _______ that late movie last night, you wouldn't he sleepy.

A．belongs to a high social class
B．comes from a middle class family
C．didn't like to go bicycling with his parent
D．felt it a glory to own a bicycle

A．Positive charges are in the top of the cloud, negative charges in the bottom.
B．When positive and negative charges within a cloud cannot break down the insulating properties of air, no lightening will be formed.
C．Without hail and thunder, there could be no lightening.
D．Without refrigerated rods, lightening could not be created.