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51. | visit the excavations |
| 参观挖掘现场. |
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52. | optimum height of cut |
| 最佳挖掘高度 |
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53. | quarried products |
| 冰川挖掘产物 |
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54. | excavation without timbering |
| 无支撑挖掘 |
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55. | optimum depth of cut |
| 最佳挖掘深度 |
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56. | potato raising plough |
| 马铃薯挖掘犁 |
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57. | spiral cutter-head |
| 螺旋形挖掘头 |
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58. | grab type dredge |
| 抓斗挖掘船 |
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59. | excavating and loading teeth |
| 挖掘装载齿 |
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60. | d and gravel dredge(r) |
| 砂石挖掘船 |
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