| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a period [prep] | 1754 |
|
| 2 | [prep] a period [prep] | 1754 |
|
| 3 | over a [noun] [prep] | 1385 |
|
| 4 | over [art] period [prep] | 740 |
|
| 5 | over a period [prep] | 629 |
|
| 6 | over a period [prep] | 629 |
|
