| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] [prep] a long period | 177 |
|
| 2 | [noun] [vb pp] [prep] a long | 69 |
|
| 3 | [vb pp] [prep] a long period | 67 |
|
| 4 | [noun] [vb pp] [prep] a period | 25 |
|
