A.17/27;B.17/26;C.19/27;D.19/28;
[单选题]1/3,3/9,2/3,13/21,()A .17/27B .17/26C .19/27D .19/28
[单选题]:1,4/3,13/9,40/27,()。A.121/81 B.67/81 C.121/51 D.67/51
[单选题]1,4/3,13/9,40/27,()。A.121/81 B.67/81 C.121/51 D.67/51
[单选题]2/3,3/5,5/8,9/13,()A.2/3B.5/7C.16/21D.17/22
[单选题]:1+1,2+3,3+5,1+7,2+9,3+11,1+13,…第40项为( )A.1+83 B.1+81 C.1+79 D.1+77
[单选题]1+1,2+3,3+5,1+7,2+9,3+11,1+13,…第40项为( )A.1+83 B.1+81 C.1+79 D.1+77
[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
[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