开采

And we live in such a generous nature that gestates so many treasures for human's development. However, we, human, recklessly destroy in return. We do need to protect the earth and the nature with our hearts from now on.

再说了大自然真是慷慨，孕育出这么多宝藏，供人类使用，而我们却任意地破坏资源，毫无节制地开采，从现在起，我们应该好好保护地球，保护大自然！

History has glamorized the gold rushes to California and Alaska, and the silver finds in Nevada.

美国历史虽然曾对加利福尼亚州和阿拉斯加州的淘金热以及内华达州银矿的发现作过动人的描绘，然而美国当今的黄金年产值（14亿美元）和白银年产值都大大低于石油、铜、铁、煤及其他开采的金属。

History has glamorized the gold rushes to California and Alaska,and the silver finds in Nevada.

美国历史虽然曾对加利福尼亚州和阿拉斯加州的淘金暖以及内华达州银矿的发现作过动人的描绘，然而美国当今的黄金年产值1.4亿美元和白银年产值(1.5亿美元都大大低于石油250亿美元、铜、铁、煤及其他开采的金属。

History has glamorized the gold rushes to California and Alaska, and the silver finds in Nevada.

美国历史虽然曾对加利福尼亚州和阿拉斯加州的淘金热以及内华达州银矿的发现作过动人的描绘，然而美国当今的黄金年产值(1、4亿美元)和白银年产值(1、5亿美元)都大大低于石油(250亿美元)、铜、铁、煤及其他开采的金属。

History has glamorized the gold rushes to California and Alaska, and the silver finds in Nevada. Yet America's yearly production of gold ($140 million) and silver ($150 million) is now valued far less than the oil ($25,000 million), copper, iron, coal and other minerals it mines.

美国历史虽然曾对加利福尼亚州和阿拉斯加州的淘金热以及内华达州银矿的发现作过动人的描绘，然而美国当今的黄金年产值(1、4亿美元)和白银年产值(1、5亿美元)都低于石油(250亿美元)、铜、铁、煤及其他开采的金属。

History has glamorized the gold rushes to California Alaska, the silver finds in Nevada. Yet America's yearly production of gold ($140 million) silver ($150 million) is now valued far less than the oil ($25,000 million), copper, iron, coal other minerals it mines.

美国历史虽然曾对加利福尼亚州和阿拉斯加州的淘金热以及内华达州银矿的发现作过动人的描绘，然而美国当今的黄金年产值(1、4亿美元)和白银年产值(1、5亿美元)都大大低于石油(250亿美元)、铜、铁、煤及其他开采的金属。

History has glamorized the gold rushes to California and Alaska, and the silver find s in Nevada. Yet America's yearly production of gold ($140 million) and silver ($150 million) is now valued far less than the oil ($25,000 million), copper, iron, coal and other minerals it mine s.

美国历史虽然曾对加利福尼亚州和阿拉斯加州的淘金热以及内华达州银矿的发现作过动人的描绘，然而美国当今的黄金年产值(1.4亿美元)和白银年产值(1.5亿美元)都大大低于石油(250亿美元)、铜、铁、煤及其他开采的金属。

Underground, a wealth of minerals provides a solid base for American industry. History has glamorized the gold rushes to California and Alaska, and the silver finds in Nevada. Yet America's yearly production of gold ($140 million) and silver ($150 million) is now valued far less than the oil ($25,000 million), copper, iron, coal and other minerals it mines.

mineral production.5、丰富的地下矿藏是美国工业的坚实基矗美国历史虽然曾对加利福尼亚州和阿拉斯加州的淘金热以及内华达州银矿的发现作过动人的描绘，然而美国当今的黄金年产值(1、4亿美元)和白银年产值(1、5亿美元)都大大低于石油(250亿美元)、铜、铁、煤及其他开采的金属。

History has glamorized the gold rushes to California and Alaska,and the silver finds in Nevada. Yet America's yearly production of gold ($140 million) and silver ($150 million) is now valued far less than the oil ($25,000 million),copper,iron,coal and other minerals it mines.

美国历史虽然曾对加利福尼亚州和阿拉斯加州的淘金热以及内华达州银矿的发现作过动人的描绘，然而美国当今的黄金年产值(1，4亿美元)和白银年产值(1，5亿美元)都大大低于石油(250亿美元)，铜，铁，煤及其他开采的金属。

History has glamorized the gold rushes to California and Alaska, and the silver finds in Nevada. Yet Americas yearly production of gold ($140 million) and silver ($150 million) is now valued far less than the oil ($25,000 million), copper, iron, coal and other minerals it mines.

美国历史虽然曾对加利福尼亚州和阿拉斯加州的淘金热以及内华达州银矿的发现作过动人的描绘，然而美国当今的黄金年产值(1、4亿美元)和白银年产值(1、5亿美元)都大大低于石油(250亿美元)、铜、铁、煤及其他开采的金属。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。