| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] period of | 584 |
|
| 2 | [to-vb] [prep] a [adj] period | 30 |
|
| 3 | [to-vb] [prep] a period of | 18 |
|
| 4 | [to-vb] a [adj] period of | 14 |
|
| 5 | [to-vb] [prep] [adj] period of | 5 |
|
