| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] [prep] a long period | 137 |
|
| 2 | [noun] [noun pl] [prep] a period | 32 |
|
| 3 | [noun pl] [prep] a long period | 29 |
|
| 4 | [noun] [noun pl] [prep] a long | 25 |
|
