| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | only [prep] a [adj] period [prep] | 12 |
|
| 2 | only [prep] a [adj] period [prep] | 11 |
|
| 3 | only [prep] a [adj] period of | 10 |
|
| 4 | only [prep] a [adj] period of | 10 |
|
| 5 | only for a [adj] period [prep] | 6 |
|
| 6 | only after a [adj] period [prep] | 5 |
|
