frequency spectrum
| direct vision method
| frequency spectrum abbr. | |
| tech. | 频率谱 |
| direct vision method abbr. | |
| met. | 直接目测法; 直接目测法 |
| tech. | 直接显影法; 直观法 |
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| 频率谱 | |||
| ★ 频谱 | |||
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frequency spectrum : 109 phrases in 23 subjects |