When the well reaches a pool, oil usually rises up the well because of its density difference with water beneath it or because of the pressure of expanding gas trapped above it.

当井和一个水池相接时，油通常会从井里上升，因为它与井下的水的密度不同，或者因为停留在它上方的膨胀气体的压力。

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The plan calls for rebuilding, moving and expanding the park's playground and bathrooms and creating gardens and pathways and a storm-water system to prevent flooding.

这个方案需要整座公园重新设计，搬迁，扩大原有的娱乐场和盥洗室，新盖一个花园和公园小路，以及一个预防海水泛滥的堤坝系统。

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Evans says previously researchers had proposed that the stratum corneum had a structure that was capable of expanding as it absorbed water.

在此之前，埃文斯说，研究人员提出皮肤角质层中有一种结构在吸水时会扩张。

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By expanding access to clean water, children are less at risk of being crippled by polio.

WHITEHOUSE: Dream Big: Water

But with expanding populations and dwindling water supplies, that water equation is changing.

NPR: Struggling over Water: A Series Overview

These include opening the doors of credit for the poor, simplifying and reducing barriers of entry, liberating education markets, expanding access to clean water, and improving the rule of law.

FORBES: From Aid To Enterprise: How To Intelligently Cure Poverty