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Border Points: Each cluster has a limited number of defined "border points" – these are the gateways in and out of the cluster.，这一点在WPS官方版本下载中也有详细论述
And then they had a minor breakthrough. The team discovered that a sofa seen in some of the images was only sold regionally, not nationally, and therefore had a more limited customer base.，详情可参考快连下载安装
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