全部

1·In most cases, extracting oil involves chopping down the forest that blankets the region, draining the boggy ground, stripping off the topsoil and literally digging up the oily sand below.

在大多数情况下，要从油沙中提炼出石油需要先把覆盖该地区的森林砍掉，排干地面的水分，去掉表层土然后当然就是把地下的油沙挖出来。

2·Excavation generally starts with the separate stripping of the organic topsoil, which is later reused for landscaping around the new structure.

通常土方发掘先将有机表土分别挖除，竣工后还可将其用于新修建物周围景观工程。