| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | for a [adj] period [prep] | 320 |
|
| 2 | [vb past] a [adj] period [prep] | 48 |
|
| 3 | [vb past] for a [adj] period | 11 |
|
| 4 | [vb past] for a period [prep] | 5 |
|
