First listen and then answer the following question.
What do oilmen want to achieve as soon as they strike oil?
The deepest holes of all are made for oil, and they go down to as much as 25,000 feet. But we do not need to send men down to get the oil out, as we must with other mineral deposits. The holes are only borings, less than a foot in diameter. My particular experience is largely in oil, and the search for oil has done more to improve deep drilling than any other mining activity. When it has been decided where we are going to drill, we put up at the surface an oil derrick. It has to be tall because it is like a giant block and tackle, and we have to lower into the ground and haul out of the ground great lengths of drill pipe which are rotated by an engine at the top and are fitted with a cutting bit at the bottom.
The geologist needs to know what rocks the drill has reached, so every so often a sample is obtained with a coring bit. It cuts a clean cylinder of rock, from which can be seen the strata the drill has been cutting through. Once we get down to the oil, it usually flows to the surface because great pressure, either from gas or water, is pushing it. This pressure must be under control, and we control it by means of the mud which we circulate down the drill pipe. We endeavour to avoid the old, romantic idea of a gusher, which wastes oil and gas. We want it to stay down the hole until we can lead it off in a controlled manner.
T.F.GASKELL The Search for the Earth's Minerals from Discovery
An oil rig drilling in the Abu Dhabi offshore oilfields in the Persian Gulf
New words and expressions 生词和短语
mineral adj. 矿物的
boring n. 钻孔
derrick n. 井架
block and tackle 滑轮组
haul v. 拖，拉
rotate v. 使转动
cutting bit 钻头
geologist n. 地质学家
coring bit 取芯钻头
cylinder n. 圆柱体
strata n. 岩层[复]([单]stratum或strata [误用])
circulate v. 注入，环流
gusher n. 喷油井
Notes on the text 课文注释
1.they go down to as much as 25,0000 feet，as much as意为“多达”，“达到（量）”。
as+形容词+as表示“……达”，例如：as long as长达……，as tall as高达……，as expensive as贵至……。
例句：The rain could last for as long as several weeks in summer.
2.as we must with other mineral deposits，must后面省去了与上句中相同的部分send men down。
3.a foot in diameter，直径一英尺。
4.every so often，时常。
例句：I no longer see John regularly, but every so often he drops in at my office.
5.obtain a sample，取样。
To obtain something means to get it or achieve it. (FORMAL)获得，取得某物。
例句：Where can I obtain a copy of her latest book?
例句：He always manages to obtain what he wants.
形容词形式为obtainable：If something is obtainable, it is possible to get or achieve it.
例句：The timetable is obtainable post-free from the airline office.
6.be under control处于控制之下。
例句：The fire has been brought under control.
例句：You must get your spending under control.
7.by means of，用……，靠……手段。
例句：They succeeded by means of hard working.
例句：They were able to position the yacht by means of radar.
If you endeavour to do something, you try very hard to do it. 同义词组喂strive to。
例句：They endeavoured to make her happy but in vain.
例句：Strive to build China into a powerful socialist country!