A:①②
B:③⑤
C:②⑤
D:①③
下列函数中,是二次函数的是( )
一块正方形磁砖的边长是8分米,它的面积是多少平方分米?合多少平方厘米?
— Long time no see. How have you been recently?
— . I'm sure my future will be better and better.