| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] over a long period and | 5 |
|
| 2 | [verb] [prep] a long period and | 5 |
|
| 3 | [vb pp] [prep] a long period and | 5 |
|
| 4 | [verb] over a long period and | 5 |
|
