A down - hole autotracking well pumping unit different from the conventional pumping unit was designed.针对抽油技术的现状和存在的问题,设计了一种不同于有杆抽油方法的井下自动跟踪式抽油装置.It is autumn and they are pumping water out of the swimming pool.入秋了, 他们正在...
The baroque church of San Leonardo is worth a quick look.圣莱昂纳多的巴洛克式教堂值得一看。Much of what we know about Leonardo's scientific ideas comes from his codices.我们所知有关里奥那多的科学想法大多来自于他的手抄本.The concept can be compared to Max Er...
Today, thirty - one Hawaiian species are federally as endangered or threatened.今天, 有 三十一 种鸟类已被列为濒危鸟类.It has even been granted its own federally funded economic development agency.安大略甚至获准建立自己的联邦基金经济发展机构.Still others fear ...
Kaolin forms pseudo - hexagonal plates, often regularly arranged in book - like or vermicular stacks.高岭石呈假六边形片体, 往往以书页 状 或蠕虫状规则排列.Rock fragments, including volcanics, are common, and the matrix consists largely of kaolin...