Water vapor accounts for about 4% by volume in moist areas.

在气候潮湿地区，水汽按体积占(空气体积)4%左右。

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Water vapor in the lower atmosphere can vary in amount from a mere trace in arid regions to about 4% by volume in moist areas.

大气低层的水汽量在干燥地区（量）甚微，而在潮湿地区按体积占4%左右。

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Locust eggs depend on soil moisture for their development, and both low and high rainfall can benefit them, as receding water levels and formerly flooded areas provide moist soil.

蝗虫的卵依赖潮湿的泥土来发育，较少的和较多的降雨都会有益于它们生长，因为水位下降和曾经发过洪水的地方都有潮湿的泥土。

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Wide views of impossibly deep gulches gave way to dark, moist areas canopied with prehistoric-sized leaves.

WSJ: Driving the Hana Highway in Maui, Hawaii