| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a [adj] period of | 842 |
|
| 2 | in a period of | 119 |
|
| 3 | in a [adj] period | 98 |
|
| 4 | in [adj] period of | 58 |
|
| 5 | in a [adj] of | 35 |
|
