| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun sg] [prep] a period of | 424 |
|
| 2 | and [prep] a period of | 23 |
|
| 3 | [noun sg] and [prep] a period | 12 |
|
| 4 | [noun sg] and a period of | 8 |
|
