| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a [adj] period | 462 |
|
| 2 | [vb pp] over a [adj] | 232 |
|
| 3 | [vb pp] over a period | 78 |
|
| 4 | [vb pp] a [adj] period | 23 |
|
