| |||
low/medium frequency | |||
low frequency/medium frequency | |||
| |||
low frequency/medium frequency |
低频/ 中频 : 18 phrases in 10 subjects |
Air defense | 1 |
Aviation | 4 |
Construction | 1 |
Electronics | 4 |
General | 2 |
Geophysics | 2 |
Project management | 1 |
Radio | 1 |
Space | 1 |
Technology | 1 |