“坐地日行八万里,巡天遥看一千河”中的“地”准确地说是指
A:本初子午线
B:回归线
C:赤道
D:极圈
— Did you listen to the program yesterday?
— Yes. I can't believe I heard her singing ______ the radio.
如图,在△ABC中,D,E,F分别为BC,AC,AB边的中点,AH⊥BC于H,FD=12,则HE等于( )