:5/7,7/12,12/19,19/31,( )。
A.31/49
B.1/39
C.31/50
D.50/31
[单选题]5/7,7/12,12/19,19/31,( )。A.31/49B.1/39C.31/50D.50/31
[单选题]1/3,4/7,7/11,2/3,13/19,( )A.16/21B.16/23C.18/21D.17/21
[单选题]1/3,4/7,7/11,2/3,13/19,()A.16/21B.16/23C.18/21D.17/21
[主观题]2/3,1/2,3/7,7/18,()A、4/11;B、5/12;C、7/15;D、3/16
[单选题]7, 8, 11, 7, 15, ( ), 19,5A.8B.6C.11D.19
[单选题]7 11 13 17 19 31 47 41 ( )A.63 B.195 C.55 D.5
[单选题]7,8,11,7,15,( ),19,5A.8 B.6 C.11 D.19
[单选题]5,7,9,( ),15,19。A.11B.12C.13D.14
[单选题]-2,6,6,-12,12,-36,()A.144B.-108C.-196D.256
[单选题]4,6,5,7,7,9,11,13,19,21,( )A. 27,29B. 32,33C. 35,37D.41,43