| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] over a period of | 289 |
|
| 2 | [adj] [noun] over a period | 111 |
|
| 3 | [adj] over a period of | 27 |
|
| 4 | [adj] [noun] a period of | 9 |
|
