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| ball-and-ring method | |||
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| ball and ring method | |||
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| ball-and-ring method | |||
| 球环法: 25 phrases in 12 subjects |
| Architecture | 1 |
| Baseball | 1 |
| Electronics | 1 |
| General | 1 |
| Hydroelectric power stations | 1 |
| Metallurgy | 4 |
| Oil / petroleum | 3 |
| Plastics | 3 |
| Polymers | 3 |
| Technology | 5 |
| Textile industry | 1 |
| United Nations | 1 |