| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [was/were] [verb] over a period [prep] | 15 |
|
| 2 | [was/were] [vb pp] over a period [prep] | 15 |
|
| 3 | [was/were] [verb] over a period [prep] | 15 |
|
| 4 | [was/were] [verb] over a period of | 15 |
|
| 5 | was [verb] over a period [prep] | 11 |
|
