| in preventing fading of precious items | 13 | purpose |
| very | 7 | degree |
| particularly | 4 | degree |
| skylight → be → useful | 9 |
| skylight → allow → helpful | 9 |
| skylight → be → helpful | 4 |
| negative | neutral | positive |
| 0.004 | 0.140 | 0.856 |
| Raw frequency | 22 |
| Normalized frequency | 0.510 |
| Modifier score | 0.600 |
| Perplexity | 183.591 |