排水管道 : 66 phrases in 13 subjects |
Agriculture | 6 |
Animal husbandry | 1 |
Architecture | 1 |
Bridge construction | 2 |
Ecology | 2 |
Electronics | 1 |
Engineering geology | 2 |
Hydroelectric power stations | 8 |
Hydrology | 1 |
Nautical | 1 |
Rail transport | 2 |
Technology | 38 |
Water resources | 1 |