| |||
difference set | |||
difference set (合) |
差集: 35 phrases in 12 subjects |
Air defense | 1 |
Aviation | 1 |
Business | 5 |
Cryptography | 3 |
Electric machinery | 2 |
Hydroelectric power stations | 3 |
Information technology | 1 |
Mathematics | 3 |
Oil / petroleum | 3 |
Space | 2 |
Technology | 9 |
Water resources | 2 |