| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] over a period [prep] | 60 |
|
| 2 | [verb] over a long period | 30 |
|
| 3 | [verb] a long period [prep] | 26 |
|
| 4 | over a long period [prep] | 9 |
|
