| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a [noun sg] [prep] a [adj] period | 29 |
|
| 2 | a [noun] for a [adj] period | 12 |
|
| 3 | a [noun] [prep] a fixed period | 5 |
|
| 4 | a [noun] over a [adj] period | 5 |
|
