2,2,0,7,9,9,()
A.13
B.15
C.18
D.20
:2,2,0,7,9,9,() A.13B.12C.18D.17
2,2,0,7,9,9,() A.13B.12C.18D.17
2,2,0,7,9,9.()A.13 B.12C. 18D. 17
10,1,3,7,()。 A.13B.15C.18D.21
67,54,46,35,29,()。 A.13B.15C.18D.20
2,2,0,7,9,9,()A.13B.12C.18D.17