A .3/4
B .1/4
C .2/5
D .5/6
[试题]2,1,2/3,1/2,()A、3/4;B、1/4;C、2/5;D、5/6;
[试题]2,1,2/3,1/2,()A、3/4;B、1/4;C、2/5;D、5/6;
[单选题]1/2,1,2/3,3/4,5/7,()A.7/11B.8/11C.7/13D.8/13
[试题]1/2,1/6,1/3,2,(),3,1/2A.4;B.5;C.6;D.9
[单选题]:2/3,1/2,2/5,1/3,2/7,( )。A.1/4 B.1/6 C.2/11 D.2/9
[单选题]2/3,1/2,2/5,1/3,2/7,( )。A.1/4B.1/6C.2/11D.2/9
[单选题]:1×3,2×2,1×1,2×3,1×2,2×1,1×3,…第40项为( )A.1×3 B.2×3 C.3×1 D.2×1
[单选题]1×3,2×2,1×1,2×3,1×2,2×1,1×3,…第40项为( )A.1×3 B.2×3 C.3×1 D.2×1
[单选题]2/3,1/4,2/5,(),2/7,1/16,A.1/5;B.1/17;c.1/22;d.1/9
[单选题]2/3,1/4,2/5,(),2/7,1/16,A.1/5;B.1/17;C.1/22;D.1/9;