| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a [noun] | 2521 |
|
| 2 | [prep] a period | 2137 |
|
| 3 | over [art] period | 995 |
|
| 4 | over [art] period | 995 |
|
| 5 | over a period | 682 |
|
