 |
| |||
| 频率跟踪 | |||
|
frequency- tracking : 14 phrases in 7 subjects |
| Air defense | 3 |
| Aviation | 1 |
| Communications | 1 |
| Electronics | 4 |
| Shipbuilding | 2 |
| Space | 2 |
| Telecommunications | 1 |
|
| |||
| 频率跟踪 | |||
|
frequency- tracking : 14 phrases in 7 subjects |
| Air defense | 3 |
| Aviation | 1 |
| Communications | 1 |
| Electronics | 4 |
| Shipbuilding | 2 |
| Space | 2 |
| Telecommunications | 1 |