| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] [prep] long periods of | 12 |
|
| 2 | [adv] [prep] long period of | 12 |
|
| 3 | [adv] [prep] long period of | 11 |
|
| 4 | [adv] [prep] long period of | 9 |
|
| 5 | [adv] for long period of | 7 |
|
