| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | and [noun] [prep] a period of | 12 |
|
| 2 | and [noun] [prep] a period of | 12 |
|
| 3 | and [noun] over a period of | 7 |
|
| 4 | and [noun] over a period of | 7 |
|
| 5 | and [noun pl] [prep] a period of | 5 |
|
