| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [vb pp] over a period | 46 |
|
| 2 | [vb pp] over a long period | 44 |
|
| 3 | be [vb pp] over a long | 26 |
|
| 4 | be [vb pp] over long period | 5 |
|
