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频率 分 配 : 50 phrases in 14 subjects |
Air defense | 4 |
Aviation | 1 |
Communications | 1 |
Earth sciences | 1 |
Electronics | 16 |
General | 2 |
Geophysics | 3 |
Information technology | 3 |
Mathematics | 1 |
Oil / petroleum | 1 |
Space | 5 |
Statistics | 2 |
Technology | 5 |
Telecommunications | 5 |