| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a [noun sg] [prep] a [adj] period | 38 |
|
| 2 | a [noun] [prep] a [adj] period | 29 |
|
| 3 | a [noun] for a [adj] period | 20 |
|
| 4 | an [noun] [prep] a [adj] period | 9 |
|
| 5 | a [noun] [prep] a fixed period | 6 |
|
| 6 | a [noun] over a [adj] period | 5 |
|
| 7 | a [noun] [prep] a long period | 5 |
|
