| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] long period [prep] | 24 |
|
| 2 | [adv] long period of | 21 |
|
| 3 | very long period [prep] | 10 |
|
| 4 | very long period [prep] | 10 |
|
| 5 | relatively long period [prep] | 5 |
|
| 6 | relatively long period [prep] | 5 |
|
