| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [Wh det] it [is] difficult [to-vb] [noun] | 5 |
|
| 2 | [Wh det] it is difficult [to-vb] [noun] | 5 |
|
| 3 | which it [be] difficult [to-vb] [noun] | 5 |
|
| 4 | [Wh det] it be difficult [to-vb] [noun] | 5 |
|
