He had to carry water and dig up the red earth and mix it into a stiff clay.

他要取水挖掘红泥，并把它混成稠密的粘土。

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When the tunnel is driven through stiff clay, the flow of water may be small enough to be removed by pumping.

当隧道穿越粘稠土质时，水的流量也许会小到用水泵就可以抽干。

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Then, with the withering of dry and cold climate, there appeared stiff clay sediment in the delta of the Changjiang River.

随着干冷气候的减弱，长江三角洲一带出现硬粘土沉积。

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