| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] [prep] a period of | 372 |
|
| 2 | and [prep] a period of | 23 |
|
| 3 | and [verb] [prep] a period | 14 |
|
| 4 | and [verb] a period of | 13 |
|
