| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] [adv] a long period of | 7 |
|
| 2 | [adv] [prep] a long period of | 15 |
|
| 3 | [adv] [prep] a long period of | 15 |
|
| 4 | [adv] over a long period of | 8 |
|
| 5 | [adv] over a long period of | 8 |
|
| 6 | [adv] a long period of time | 11 |
|
| 7 | [adv] a long period of [noun] | 11 |
|
| 8 | [adv] a long period of time | 11 |
|
| 9 | [adv] a long period of [noun sg] | 11 |
|
