讨论文件
DP16661永动机:三个非洲国家的人的流动性和空间摩擦
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![](../../../../../../../../../../var/folders/34/zq18d8kx7kbgby0j06p_j6t40000gn/T/TemporaryItems/NSIRD_screencaptureui_EM2XPo/Screenshot 2022-01-04 at 17.01.16.png)
- 空间摩擦 ![](../../../../../../../../../../var/folders/34/zq18d8kx7kbgby0j06p_j6t40000gn/T/TemporaryItems/NSIRD_screencaptureui_EM2XPo/Screenshot 2022-01-04 at 17.01.16.png)
- 流动性 ![](../../../../../../../../../../var/folders/34/zq18d8kx7kbgby0j06p_j6t40000gn/T/TemporaryItems/NSIRD_screencaptureui_EM2XPo/Screenshot 2022-01-04 at 17.01.16.png)
- 城市 ![](../../../../../../../../../../var/folders/34/zq18d8kx7kbgby0j06p_j6t40000gn/T/TemporaryItems/NSIRD_screencaptureui_EM2XPo/Screenshot 2022-01-04 at 17.01.16.png)
- 撒哈拉以南非洲