| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] [noun sg] over a period [prep] | 25 |
|
| 2 | [prep] [noun sg] over a period of | 24 |
|
| 3 | in [noun sg] over a period [prep] | 9 |
|
| 4 | of [noun sg] over a period [prep] | 8 |
|
