| |||
| 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 |
| Economics | 1 |
| Electronics | 1 |
| Geophysics | 2 |
| Hydroelectric power stations | 1 |
| Technology | 1 |
| |||
| 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 |
| Economics | 1 |
| Electronics | 1 |
| Geophysics | 2 |
| Hydroelectric power stations | 1 |
| Technology | 1 |