| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pers pn] [prep] a period of | 15 |
|
| 2 | [pron] over a period of | 7 |
|
| 3 | it [prep] a period of | 6 |
|
| 4 | it [prep] a period of | 6 |
|
| 5 | they [prep] a period of | 5 |
|
| 6 | [pron] for a period of | 5 |
|
| 7 | them [prep] a period of | 5 |
|
