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高频谱 : 29 phrases in 11 subjects |
| Air defense | 1 |
| Aviation | 1 |
| Chemistry | 1 |
| Earth sciences | 1 |
| Electronics | 4 |
| General | 2 |
| Geology | 1 |
| Geophysics | 2 |
| Metallurgy | 1 |
| Space | 1 |
| Technology | 14 |
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