| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | or [prep] a [adj] period | 13 |
|
| 2 | or [prep] a [adj] period | 10 |
|
| 3 | or over a [adj] period | 6 |
|
| 4 | or [prep] a long period | 6 |
|
| 5 | or over a [adj] period | 6 |
|
