| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [to-vb] [prep] a few hours | 10 |
|
| 2 | [to-vb] [prep] a few hours | 10 |
|
| 3 | [to-vb] for a few hours | 7 |
|
| 4 | [to-vb] for a few hours | 7 |
|
