| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a long period of time | 88 |
|
| 2 | over a long period of time | 71 |
|
| 3 | over a long period of time | 71 |
|
| 4 | for a long period of time | 14 |
|
| 5 | for a long period of time | 14 |
|
