| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] over a long period | 46 |
|
| 2 | [vb pp] over a long period | 44 |
|
| 3 | [verb] over a long period | 35 |
|
| 4 | [verb] over a longer period | 11 |
|
