| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adj] [prep] a long period | 14 |
|
| 2 | [adj] [prep] a long period | 13 |
|
| 3 | [adj] for a long period | 11 |
|
| 4 | [adj] over a long period | 6 |
|
