| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] [prep] a long period of | 31 |
|
| 2 | [verb] [prep] a long period of | 31 |
|
| 3 | [verb] [prep] a long period of | 31 |
|
| 4 | [vb pp] [prep] a long period of | 24 |
|
| 5 | [verb] over a long period of | 13 |
|
| 6 | [verb] over a long period of | 13 |
|
| 7 | [verb] for a long period of | 7 |
|
| 8 | [verb] for a long period of | 7 |
|
