| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [be] difficult [to-vb] [conj] | 233 |
|
| 2 | it [be] not difficult [to-vb] | 185 |
|
| 3 | [be] not difficult [to-vb] [conj] | 28 |
|
| 4 | it [be] not [to-vb] [conj] | 5 |
|
