长t

t
0
4
t
0
5
t
0
5
t
0
4
t
0
4
t
0
8
t
0
4
t
0
6
t
0
6
t
0
4
t
0
4
t
0
2
t
0
4
t
0
4
t
0
3
t
0
6
t
0
3
t
0
4