A:①②
B:①③
C:②③
D:②④
Could you record today's NBA basketball game for me? I can watch ________ later.
物质
a
b
c
d
反应前的质量/g
6.4
4.0
3.2
2.8
反应后的质量/g
5.2
7.2
x
关于位移和路程,下列说法中正确的是( )