| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a period of a [adj] | 12 |
|
| 2 | over a period of [art] few | 11 |
|
| 3 | over a period of [art] [det] | 11 |
|
| 4 | over a period of [art] few | 11 |
|
