| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] [prep] a fixed period of | 6 |
|
| 2 | [verb] [prep] a fixed period of | 6 |
|
| 3 | [verb] [prep] a fixed period of | 6 |
|
| 4 | [verb] for a fixed period of | 5 |
|
| 5 | [verb] for a fixed period of | 5 |
|
