 |
|
drill steel : 60 phrases in 15 subjects |
| Bridge construction | 1 |
| Construction | 1 |
| Drilling | 6 |
| Electronics | 1 |
| Geology | 2 |
| Gold mining | 2 |
| Industry | 1 |
| Mechanics | 2 |
| Metallurgy | 3 |
| Military | 2 |
| Mining | 17 |
| Oil / petroleum | 10 |
| Oil and gas | 7 |
| Oil and gas technology | 1 |
| Technology | 4 |