| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] a [noun] of | 17382 |
|
| 2 | [adv] [art] period of | 137 |
|
| 3 | [adv] [art] period of | 137 |
|
| 4 | [adv] a period [prep] | 117 |
|
| 5 | [adv] a period [prep] | 117 |
|
| 6 | [adv] a period of | 110 |
|
| 7 | [adv] a period of | 110 |
|
