---________ do you like giraffes?
--- Because they are beautiful.
A:Why
B:When
C:How
若 x-2y3y-x=23,则yx为( )
如图①,∠QPN的顶点P在正方形ABCD两条对角线的交点处,∠QPN=α,∠QPN的两边分别与正方形ABCD的边AD和CD交于点E和点F(点F与点C、D不重合).