| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [been] [vb pp] over a [adj] period | 8 |
|
| 2 | been [vb pp] over a [adj] period | 8 |
|
| 3 | [been] [vb pp] over a long period | 5 |
|
| 4 | [been] [vb pp] over a long period | 5 |
|
