| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adj] hours difficulty | 12 |
|
| 2 | [num] hours difficulty | 12 |
|
| 3 | hours difficulty [num] | 12 |
|
| 4 | hours difficulty [adj] | 12 |
|
| 5 | hours difficulty 3 | 5 |
|
| 6 | hours difficulty 3 | 5 |
|
