A:It’s easier said than done.
B:He who laughs last laughs best.
C:You are trying to teach your granny how to suck eggs.
D:You can take a horse to the water but you cannot make him drink
将二次函数y=x2﹣4x+5化为y=(x﹣h)2+k的形式,那么h+k=____
8÷2=____