| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [is] difficult [to-vb] | 1809 |
|
| 2 | [coord] it [is] difficult | 260 |
|
| 3 | [coord] it [is] [to-vb] | 36 |
|
| 4 | [coord] [is] difficult [to-vb] | 19 |
|
