| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over [art] long period of | 85 |
|
| 2 | over a long period of | 84 |
|
| 3 | over a long period of | 84 |
|
| 4 | over [art] long period of | 78 |
|
| 5 | over [art] longer period of | 7 |
|
