What is "someone you can't live without"?

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回答: "通奸"算爱情吗?zhenghueng2010-04-26 14:29:36

如何定量描述?For example, there are two real roots when b*b-4*a*c>0, while there are two complex roots when b*b-4*a*c

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回复:What is "someone you can't live without"? -ragnarok- 给 ragnarok 发送悄悄话 (564 bytes) () 04/26/2010 postreply 15:20:32

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