| under the true french system | 5 | other |
| throughout life for good vision | 5 | purpose |
| both | 3 | degree |
| glass → be → necessary | 26 |
| glass → be → required | 24 |
| glass → be → necessity | 8 |
| glass → be → must | 8 |
| glass → be → need | 3 |
| negative | neutral | positive |
| 0.180 | 0.545 | 0.275 |
| Raw frequency | 69 |
| Normalized frequency | 0.495 |
| Modifier score | 0.000 |
| Perplexity | 129.393 |