| to prevent polluting the groundwater | 5 | purpose |
| usually | 3 | temporal |
| landfill → have → liner | 5 |
| landfill → have → liner systems | 3 |
| negative | neutral | positive |
| 0.243 | 0.692 | 0.065 |
| Raw frequency | 8 |
| Normalized frequency | 0.270 |
| Modifier score | 0.800 |
| Perplexity | 396.788 |