| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a period [prep] | 62 |
|
| 2 | over a period [prep] | 62 |
|
| 3 | over a period [prep] | 62 |
|
| 4 | over a period of | 61 |
|
| 5 | over a period of | 61 |
|
