—John is so excited. Did he win the competition? —Yes. He was lucky and he had one minute to complete the special task, no more and no less.
A:especially
B:probably
C:exactly
D:hardly
在南极上空看,甲机沿南极圈作逆时针方向飞行;在北极上空看,乙机沿北极圈作顺时针方向飞行,这两架飞机的飞行方向( )
如图所示,AB=CD,BC=DA,E,F是AC上的两点,且AE=CF,求证:BF=DE.