| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [conj] [noun pl] [prep] a period of | 6 |
|
| 2 | [coord] [noun pl] [prep] a period [prep] | 5 |
|
| 3 | and [noun pl] [prep] a period [prep] | 5 |
|
| 4 | and [noun pl] [prep] a period [prep] | 5 |
|
