13-1. The deepest holes of all are made for oil, and they go down to as much as 25,000 feet.

【译文】在所有洞穴中，为寻找石油而钻的洞最深。这些洞可深达25,000英尺。

【讲解】go down to as much as…等于get as far as…。much相当于deep。they指holes。

13-2. But we do not need to send men down to get the oil out, as we must with other mineral deposits.

【译文】但我们不必像开采其他矿藏那样必须派人到地下取石油。

【讲解】as we must with other mineral deposits是方式状语从句，must后省略了send men down。with意为“对于”。

13-3. The holes are only borings, less than a foot in diameter.

【译文】这些洞不过是些直径不足1英尺的钻孔。

【讲解】a foot in diameter意为“直径1英尺”。

【单词和短语】

由diameter(直径)联想到radius(半径)和perimeter(周长)。

13-4. My particular experience is largely in oil, and the search for oil has done more to improve deep drilling than any other mining activity.

【译文】我主要从事与石油有关的工作。寻找石油比其他任何采矿活动对改进钻探技术做出的贡献都大。

【讲解】the search for oil作主语。activity后省略了has done。to improve deep drilling作方面状语，修饰has done。

13-5. When it has been decided where we are going to drill, we put up at the surface an oil derrick.

【译文】当确定钻孔地点后，我们就在地上竖起井架。

【讲解】where we are going to drill乃真正的主语，it是形式主语。an oil derrick作put up的宾语。

13-6. 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.

【译文】井架必须很高，因为它像一个巨型滑轮组。我们必须把很长的钻杆一节节地钻入地下，然后再从地下拉出来。钻杆顶部安装的发动机带动钻杆旋转，它的底部装有钻头。

【讲解】句首的it指an old derrick。great lengths of drill pipe… bottom作lower和haul的宾语。

【单词和短语】

length是量词，又如：a length of stove pipe(一节烟囱)，a length of rope(一节绳子)。

13-7. The geologist needs to know what rocks the drill has reached, so every so often a sample is obtained with a coring bit.新概念英语第三册mp3

【译文】地质学家需要知道钻头已到达什么样的岩层，因此时常要用芯钻头取样。

【讲解】the geologist中的the表示类别，指“地质学家这类人”。

【单词和短语】

every so often：时常。

13-8. It cuts a clean cylinder of rock, from which can be seen the strata the drill has been cutting through.

【译文】这种钻头能切割一段光滑的圆柱形岩石，从中能看出所钻透的地层。

【讲解】can be seen the strata…through乃倒装结构，自然语序是the strata…through can be seen。因为主语过长，倒装可以避免头重脚轻。the drill has been cutting through是定语从句，修饰strata。

13-9. Once we get down to the oil, it usually flows to the surface because great pressure, either from gas or water, is pushing it.

【译文】一旦到达油层，石油就会由于来自天然气或水巨大压力而流出地面。

【讲解】once we get down to the oil是时间状语从句，once是连接词。句中的两个it都指oil。either from gas or water乃非限制性定语，修饰pressure。

13-10. This pressure must be under control, and we control it by means of the mud which we circulate down the drill pipe.

【译文】必须对这种压力加以控制，我们用让泥桨顺着钻杆向下循环的方法来控制压力。

【讲解】it指pressure。

【单词和短语】

circulate: 环行;环流;循环(to move around within a system, or to make something do this)，

例如：

The earth circulates around the sun. 地球绕着太阳转。

Blood circulates through the body. 血液在体内循环。

13-11. We endeavour to avoid the old, romantic idea of a gusher, which wastes oil and gas.

【译文】我们尽量避免使用陈旧浪漫的、会浪费石油和天然气的喷井方法。

【讲解】of意为“关于”。

13-12. We want it to stay down the hole until we can lead it off in a controlled manner.

【译文】在用能控制的方法把石油引上来之前，我们要让它留在钻孔下面。

【讲解】句中两个it都指oil。to stay down the hole作宾语补足语。