| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a long period of [noun] | 81 |
|
| 2 | over a long period of [noun sg] | 78 |
|
| 3 | over a long period of time | 77 |
|
| 4 | over a long period of time | 77 |
|
| 5 | over a long period of [noun] | 75 |
|
| 6 | over a longer period of [noun] | 6 |
|
