| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] period | 1796 |
|
| 2 | [prep] a fixed [noun] | 522 |
|
| 3 | [prep] a fixed [noun sg] | 521 |
|
| 4 | [prep] [art] fixed period | 54 |
|
| 5 | [prep] [art] fixed period | 54 |
|
| 6 | [prep] a fixed period | 52 |
|
| 7 | [prep] a fixed period | 52 |
|
