 |
| |||
| loose bottom | |||
| free bottom | |||
| |||
| dump bottom; moving bed; traveling bed; travelling bed | |||
| 活动底: 27 phrases in 11 subjects |
| Architecture | 1 |
| Automobiles | 2 |
| Bridge construction | 1 |
| Drilling | 1 |
| Engineering geology | 1 |
| Metallurgy | 1 |
| Nautical | 1 |
| Oil / petroleum | 3 |
| Rail transport | 3 |
| Space | 1 |
| Technology | 12 |