A.21
B.20
C.19
D.18
[单选题]31 29 23 ( ) 17 13 11A.21 B. 20 C. 19 D. 18
[单选题]3,11,13,29,31,( )A. 52 B. 53 C. 54 D. 55
[单选题]11,13,17,19,23,( )A.27B.29C.31D.33
[单选题]7 11 13 17 19 31 47 41 ( )A.63 B.195 C.55 D.5
[单选题]1,1/2 , 6/11 ,17/29 , 23/38 ,( )A.28/45 B.117/191 C.31/47 D.122/199
[单选题]23 29 31 37 ( )A. 41 B. 40 C.43 D.45
[单选题]23,29,31,37,( )。A.41B.40C.43D.45
[单选题]23,29,31,37,( )。A.41B.40C.43D.45
[单选题]13, 23, 31, 44, 55, ( )A.68B.62C.71D.43
[单选题]13, 23, 31, 44, 55, ( )。