| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] period of | 544 |
|
| 2 | [conj] [prep] a [adj] period | 69 |
|
| 3 | [conj] [prep] a period of | 51 |
|
| 4 | [conj] a [adj] period of | 37 |
|
| 5 | [conj] [prep] [adj] period of | 9 |
|
| 6 | [conj] [prep] a [adj] of | 8 |
|
