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2,3,5,7,11,() A.17;B.18;C.19;D.20
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0,1/3, 5/8,5/6,9/10,()A.5/6 B.8/9 C.13/14 D.21/20
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0,1/3,5/8,5/6,9/10,()A.5/6 B.8/9 C.13/14 D.21/20
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0,1/3,5/8,5/6,9/10,() A.5/6 B.8/9 C.13/14 D.21/20
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1, 3,7, 13, ()。A.15 B.17 C.19 D.21
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2,3,5/2,8/3,13/5,()。A.15/8B.21/8C.27/10D.17/13
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5 2 5 8 13 ( )。 A. 20B. 38C. 17D. 21