| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] period of | 618 |
|
| 2 | [verb] [prep] a [adj] period | 465 |
|
| 3 | [verb] [prep] a period of | 372 |
|
| 4 | [verb] a [adj] period of | 150 |
|
| 5 | [verb] [prep] a [adj] of | 114 |
|
| 6 | [verb] [prep] [adj] period of | 43 |
|
