The reason is the spatial concentration of population and resources had the effect of increasing returns to scale.

原因是人口和资源的空间集聚产生了规模收益递增的效应。

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With rapid growth of urban economy and concentration of population, there is urgent need to construct urban tunnel and underground projects.

随着城市快速经济的增长及人口的高度集中，城市隧道及地下工程的修建日益迫切。

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It also offered that the concentration of population from natural villages to central villages should be regarded as one of the urbanization forms.

这种人口由自然村向中心村镇的集中也应看作是城市化的一种形式。

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He said it was important for the restrictions to take into account the concentration of population near a store.

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"Rising fuel prices and the increasing concentration of the population in urban areas is bringing about serious logistical problems for the delivery of food, " he says.

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The building of more freeways in relatively low-population areas will not solve the congestion problems in the cities where the concentration of buyers is located.

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