问题
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1,2,2,6,3,15,3,21,4,() A.46;B.20;C.12;D.44;
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:1, 2, 3, 7, 46, ()。A.2109B.1289C.322D.147
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1/3,4/7 ,7/11 ,2/3 ,13/19 ,()A. 16/21 B. 16/23 C. 18/21 D. 17/21
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1/3,4/7 ,7/11 ,2/3 ,13/19 ,() A. 16/21 B. 16/23 C. 18/21 D. 17/21
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1, 2, 3, 8, 21,46, ()。A.70 B.87 C.90 D.100
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1, 2, 3,8, 21,46, ()。A.70 B.87 C.90 D.100