A . 15
B . 17
C . 19
D . 21
[主观题]填空。1/3+7/13=()5/7-2/7=()()-1/12=11/127/5-()=3/5
[单选题]1,1,3,3,7,5,13,7,21,( )。A.9B.11C.8D.22
[单选题]-27,-7,1,3,5,13,( )A.33B.31C.27D.25
[单选题]1/2,1,7/8 ,5/8 ,13/32 ,( )A. 1/4B. 15/64C. 11/64D. 7/64
[单选题]:1, 3, 3, 5, 7, 9, 13, 15, ( ), ( )。A.19,21B.19,23C.2l,23D.27,30
[单选题]:1,3,3,5,7,9,13,15,( ),( )。A.19,21 B.19,23 C.21,23 D.27,30
[单选题]1,3,3,5,7,9,13,15(),()A . A:19,21B . B:19,23C . C:21,23D . D:27,30
[单选题]1/4,2/7,2/5,8/13,1( )A.9/16B.3C.32/19D.28/17
[单选题]2/15,1/5,1/3,(),13/15,7/5,34/15。A. 25 B. 815 C. 35 D. 23
[单选题]0,1/6,3/8,1/2,1/2,( )A.5/13 B7/13 C5/12 D7/12