| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] [noun sg] over a [adj] period | 29 |
|
| 2 | [prep] [noun sg] over a long period | 20 |
|
| 3 | [prep] [noun sg] over a long period | 18 |
|
| 4 | of [noun sg] over a [adj] period | 18 |
|
