| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] [prep] a fixed period | 26 |
|
| 2 | [noun sg] [prep] a fixed period | 20 |
|
| 3 | [noun] for a fixed period | 16 |
|
| 4 | [noun] for a fixed period | 16 |
|
