The formation of karst? Cavern type carbonate oil reservoirs in lower Ordovician of 4 area in Tahe oilfield is related to weathering? Denudation of fossil weathering crust.

塔河油田4区下奥陶统碳酸盐岩岩溶缝洞型油藏的形成与古风化壳的风化剥蚀有关。

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The ordinary 4-bed frame tent doesn't usually have a separate kitchen area, but the larger ones often do.

普通的四室框架帐篷通常没有单独的厨房区域，但更大的帐篷通常有。

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America's winter wheat plantings are up 4% and the spring-sown area is likely to rise more.

美国冬小麦的种植增长了4%，春季耕种面积很可能会增加更多。

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Humans have lived in the area of Yosemite for more than 4,000 years.

VOA: special.2009.01.07

So if we want to talk about the volume of that, we just talk about the surface area, which is 4 pi r squared, and we multiply that by the thickness d r.

如果我们要讨论它的体积，我们要用的是表面面积，也就是４πｒ的平方，乘以厚度ｄｒ

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