8051系列单片机内部有很强的中断功能，它共有中断源( )
A．3个
B．4个
C．5个
D．6个
参考答案：C
已知扇形AOB的半径为6cm，圆心角的度数为120 °，若将此扇形围成一个圆锥，则围成的圆锥的侧面积为（ ）cm2．
--- What’s your family rules?
--- We shouldn’t talk ____ food in our mouths while having meals.
A．with
B．in
C．of
D．at
