【例题】1,4,3,5,2,6,4,7,( ) A.1 B.2 C.3 D.4
【例题】5/12,1/3,3/4,13/12,( ),35/12 A.7/6 B.9/8 C.11/6 D.15/8
【例题】2/3,1/2,3/7,18/7,( ) A.5/9 B.4/11 C.3/13 D.2/5
【例题】5/7,7/12,12/19,19/31,( ) A.31/49 B.1/39 C.31/50 D.50/31