| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a [adj] period of | 134 |
|
| 2 | [verb] a [adj] period of | 131 |
|
| 3 | [verb] over a period of | 75 |
|
| 4 | [verb] over a [adj] period | 75 |
|
| 5 | [verb] over [adj] period of | 9 |
|
