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