| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] period of | 544 |
|
| 2 | [adv] [prep] a [adj] period | 162 |
|
| 3 | [adv] [prep] a period of | 129 |
|
| 4 | [adv] [prep] a [adj] of | 53 |
|
| 5 | [adv] a [adj] period of | 42 |
|
| 6 | [adv] [prep] [adj] period of | 15 |
|
