| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | of [noun sg] [prep] a period of | 23 |
|
| 2 | of [noun sg] [prep] a period of | 23 |
|
| 3 | of [noun sg] over a period of | 7 |
|
| 4 | of [noun sg] for a period of | 5 |
|
