| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [be] [vb pp] over a long period | 22 |
|
| 2 | be [vb pp] over a long period | 22 |
|
| 3 | [be] [vb pp] over a long period | 14 |
|
| 4 | [be] [vb pp] over a long period | 10 |
|
| 5 | be [vb pp] over a long period | 10 |
|
| 6 | [be] [vb pp] over a longer period | 8 |
|
| 7 | been [vb pp] over a long period | 5 |
|
| 8 | [been] [vb pp] over a long period | 5 |
|
