| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb past] [prep] several | 288 |
|
| 2 | [prep] several hours | 189 |
|
| 3 | [vb past] [prep] hours | 102 |
|
| 4 | [vb past] several hours | 29 |
|
