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| 复杂地区 | |||
| 有疑问的区域 | |||
| 研究地区; 难题地区 | |||
| problem area: 7 phrases in 6 subjects |
| Aviation | 1 |
| Economy | 1 |
| Electronics | 1 |
| Geophysics | 2 |
| Hydroelectric power stations | 1 |
| Technology | 1 |
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