| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] [prep] a period of | 129 |
|
| 2 | [adv] over a [noun] of | 114 |
|
| 3 | [adv] over [art] period of | 68 |
|
| 4 | [adv] over [art] period of | 68 |
|
| 5 | [adv] over a period of | 60 |
|
| 6 | [adv] over a period [prep] | 60 |
|
