新概念英语85年上外美音版第四册 第16课

　　Lesson 16 The Search for the Earth's Minerals 寻找地球的矿物
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 decided¹ 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 th. 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 geologist² 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 cylinder³ of rock, from which can be seen he strata⁴ 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 gusher⁵, which wastes oil and gas. We want it tostay down the hole until we can lead it off in a controlled manner.
 

1 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

2 geologist   

n.地质学家

参考例句：

• The geologist found many uncovered fossils in the valley.在那山谷里，地质学家发现了许多裸露的化石。
• He was a geologist,rated by his cronies as the best in the business.他是一位地质学家，被他的老朋友们看做是这门行当中最好的一位。

3 cylinder   

n.圆筒，柱(面)，汽缸

参考例句：

• What's the volume of this cylinder?这个圆筒的体积有多少？
• The cylinder is getting too much gas and not enough air.汽缸里汽油太多而空气不足。

4 strata   

n.地层（复数）；社会阶层

参考例句：

• The older strata gradually disintegrate.较老的岩层渐渐风化。
• They represent all social strata.他们代表各个社会阶层。

5 gusher   

n.喷油井

参考例句：

• We endeavour to avoid the old,romantic idea of a gusher.我们力图避免那种有关喷油井的陈旧的、不切实际的计划。
• The oil rushes up the tube and spouts up as a gusher.石油会沿着钢管上涌，如同自喷井那样喷射出来。