| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] over [art] period | 49 |
|
| 2 | [adv] over a period | 39 |
|
| 3 | [adv] over a period | 39 |
|
| 4 | [adv] over the period | 10 |
|
| 5 | [adv] over the period | 10 |
|
| 6 | gradually over [art] period | 7 |
|
