| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | occur [adv] [art] period [prep] | 6 |
|
| 2 | occur [adv] [art] period [prep] | 6 |
|
| 3 | occur [adv] [art] period of | 6 |
|
| 4 | occur [adv] [art] period of | 6 |
|
