| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] [prep] [art] long period of | 32 |
|
| 2 | [verb] [prep] a long period of | 31 |
|
| 3 | [verb] [prep] a long period of | 31 |
|
| 4 | [vb pp] [prep] [art] long period of | 25 |
|
| 5 | [verb] over [art] long period of | 13 |
|
| 6 | [verb] for [art] long period of | 7 |
|
