| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | but it is [adv] difficult [to-vb] | 27 |
|
| 2 | but it is [adv] difficult [verb] | 27 |
|
| 3 | but it is [adv] difficult [verb] | 27 |
|
| 4 | but it is very difficult [verb] | 11 |
|
