| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a long period of [noun sg] | 78 |
|
| 2 | over [art] long period of time | 77 |
|
| 3 | over [art] long period of [noun sg] | 72 |
|
| 4 | over [art] longer period of [noun sg] | 6 |
|
