| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a longer period [prep] time | 10 |
|
| 2 | [prep] a longer period [prep] time | 10 |
|
| 3 | over a longer period [prep] time | 6 |
|
| 4 | over a longer period [prep] time | 6 |
|
