问题
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2,6,12,20,() A.40;B.32;C.30;D.28
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2/5,3/7,4/10,6/14,8/20,12/28,()A.224/56B.14/32C.20/48D.16/40
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2/5,3/7,4/10,6/14,8/20,12/28,() A.224/56B.14/32C.20/48D.16/40
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2/5, 3/7, 4/10, 6/14, 8/20, 12/28,______ () A.224/56 B.14/32 C.20/48 D.16/40
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2/5, 3/7, 4/10, 6/14, 8/20, 12/28, () A.224/56 B.14/32 C.20/48 D.16/40
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2,4, 6, 12, 14, (‘)A.20 B.24 C.28 D.30