| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] over a period of | 34 |
|
| 2 | together over a [noun sg] of | 7 |
|
| 3 | gradually over a [noun sg] of | 7 |
|
| 4 | [adv] over a number of | 5 |
|
