| 21. | As the men refused to stop working, the police attempted to seize the pneumatic drill . |
| 由于工人拒绝停下手中的活，警察想夺风钻。
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| 22. | When is has been decided where we are going to drill , we put up at the surface an oil derrick. |
| 当确定钻孔地点后，我们就在那里竖起一个井架。
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| 23. | 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. |
| 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。
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| 24. | The geologist needs to know what rocks the drill has reached, so every so often a sample is obtained with a coring bit. |
| 地质学家需要知道钻头已以到达什么样的岩层，因此时常要用芯钻头取样。
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| 25. | It cuts a clean cylinder of rock, from which can be seen the strata the drill has been cutting through. |
| 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。
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| 26. | This pressure must be under control, and we control it by means of the mud which we circulate down the drill pipe. |
| 这种压力必须加以控制，我们让泥桨顺着钻杆向下循环，用这种方法来控制压力。
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| 27. | The dentist's drill made a lot of noise. |
| 牙钻发出很大的噪音。
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| 28. | A forceps and a drill are two instruments used by dentists. |
| 镊子和钻头是牙科医生用的两种器械。
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| 29. | The army paraded round drill squares. |
| 军队绕训练场列队行进。
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| 30. | an electric drill with a range of different attachments |
| 带有各种配件的电钻
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