| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb pp] [prep] a long period | 53 |
|
| 2 | [vb pp] over a long period | 44 |
|
| 3 | [vb pp] for a long period | 14 |
|
| 4 | [vb pp] [prep] a longer period | 14 |
|
| 5 | developed [prep] a long period | 5 |
|
