螞蟻啊，兩棟樓有多少住戶？，兩座房有幾家住戶？住戶越多有快遞件的比例就越大。這就是密度啦。

來源: 薛成於 2016-09-07 10:33:34 [博客] [舊帖] [給我悄悄話] 本文已被閱讀：次

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