1,3,O,6,10,9,()。
A. 13
B.14
C.15
D.17
17, 10, 9, 6, 1, 2, (. )。A.O B.1 C.2 D.3
9,17,13,15,14,()A.13B.14C.13.5D.14.5
1,2,1,6,9,10,()A.13B.12C.19 D.17
9,17,13,15,14,()A.13B.14C.13.5 D.14.5
1,3,O,6,10,9,()。A. 13B.14C.15 D.17