| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] a long period | 25 |
|
| 2 | [verb] a longer period | 9 |
|
| 3 | [vb past] a long period | 9 |
|
| 4 | [vb pp] a long period | 9 |
|
| 5 | follow a long period | 5 |
|
| 6 | have a long period | 5 |
|
