| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a [adj] period of | 137 |
|
| 2 | [adj] over a [adj] period | 27 |
|
| 3 | [adj] over a period of | 27 |
|
| 4 | [adj] a [adj] period of | 11 |
|
