| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] over a long period [prep] | 9 |
|
| 2 | [adv] over a long period [prep] | 9 |
|
| 3 | [adv] over a long period of | 8 |
|
| 4 | [adv] over a long period of | 8 |
|
| 5 | [verb] [adv] over a long period | 11 |
|
| 6 | [vb pp] [adv] over a long period | 7 |
|
