—No, there is _______ in the fridge.
A:plenty
B:a plenty
C:plenty of milk
D:a plenty of
14.5×101____101
设椭圆x26+y22=1和双曲线x23-y2=1的公共焦点为F1,F2,P是两曲线的一个公共点,则cos∠F1PF2的值等于( )