| currently | 6 | temporal |
| during the mid-1960s | 5 | temporal |
| in order to keep | 4 | purpose |
| airport → be → upgraded | 32 |
| airport → undergo → upgrade | 6 |
| airport → undergone → upgrade | 3 |
| negative | neutral | positive |
| 0.030 | 0.410 | 0.560 |
| Raw frequency | 41 |
| Normalized frequency | 0.368 |
| Modifier score | 0.600 |
| Perplexity | 460.490 |