— How many _________ do you have?
—Three.
A:a notebook.
B:notebooks
C:notebook
小车的位置
A
B
C
D
E
F
距A点距离/cm
0.0
10.0
20.0
30.0
40.0
50.0
小车运动时间/s
0
5
9
12
14
15