| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] period of | 584 |
|
| 2 | [vb pp] [prep] a [adj] period | 259 |
|
| 3 | [vb pp] [prep] a period of | 215 |
|
| 4 | [vb pp] [prep] [adj] period of | 37 |
|
| 5 | [vb pp] a [adj] period of | 15 |
|
| 6 | [vb pp] [prep] a [adj] of | 5 |
|
