| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] [num] hours [adj] | 28 |
|
| 2 | for [num] hours [adj] | 11 |
|
| 3 | for [num] hours [adj] | 11 |
|
| 4 | [prep] [num] hours prior | 6 |
|
