| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adv] long period | 44 |
|
| 2 | [prep] [art] [adv] long period | 24 |
|
| 3 | over [art] [adv] long period | 22 |
|
| 4 | [prep] [art] [adv] longer period | 22 |
|
| 5 | for [art] [adv] long period | 19 |
|
| 6 | [prep] [art] much long period | 16 |
|
| 7 | [prep] [art] very long period | 8 |
|
