| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a long period of time | 98 |
|
| 2 | [prep] a long period of time | 98 |
|
| 3 | [prep] a long period of time | 88 |
|
| 4 | over a long period of time | 77 |
|
| 5 | over a long period of time | 77 |
|
| 6 | for a long period of time | 17 |
|
| 7 | for a long period of time | 17 |
|
| 8 | [prep] a longer period of time | 10 |
|
