| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [that] over a period of | 6 |
|
| 2 | [that] over a period [prep] | 6 |
|
| 3 | [that] over a period [prep] | 6 |
|
| 4 | that over a period [prep] | 6 |
|
