A:f(1)和f(2)
B:f(1)和f(﹣1)
C:f(﹣1)和f(2)
D:f(2)和f(﹣1)
There are many folk _________ about this festival.
某物体以40m/s的初速度竖直上抛,不计空气阻力,g取10m/s2,5s内物体的( )