| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb pp] [prep] a long period of | 27 |
|
| 2 | [vb pp] over a [adj] period of | 23 |
|
| 3 | [vb pp] over a long period [prep] | 16 |
|
| 4 | [verb] over a long period of | 15 |
|
| 5 | [vb pp] over [art] long period of | 14 |
|
| 6 | [vb pp] over a long [noun sg] of | 14 |
|
| 7 | [vb pp] over a long period of | 14 |
|
| 8 | [vb pp] over a long [noun] of | 14 |
|
