| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [Wh adv] it [is] difficult [verb] | 11 |
|
| 2 | [Wh adv] it [is] difficult [verb] | 11 |
|
| 3 | [Wh adv] it [is] difficult [to-vb] | 11 |
|
| 4 | [Wh adv] it is difficult [verb] | 10 |
|
