A:﹣4
B:4
C:3
D:﹣3
— Ben, what's your favorite subject, math ________ science?
— Math.
如图,在高为3米,斜坡长为5米的楼梯表面铺地毯,则地毯的长度至少需要多少米?若楼梯宽2米,地毯每平方米30元,那么这块地毯需花多少元?