| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over long periods [prep] [noun] | 20 |
|
| 2 | over long period [prep] [noun sg] | 19 |
|
| 3 | over long period of [noun] | 19 |
|
| 4 | over long period [prep] time | 19 |
|
| 5 | over long period [prep] time | 19 |
|
