| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a [adj] period | 462 |
|
| 2 | a [adj] period [conj] | 130 |
|
| 3 | over a [adj] [conj] | 12 |
|
| 4 | over a period [conj] | 6 |
|
