| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it 's [adv] difficult [verb] [subord] | 9 |
|
| 2 | it 's [adv] difficult [to-vb] [subord] | 9 |
|
| 3 | it 's very difficult [verb] [subord] | 6 |
|
