| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [be] difficult [to-vb] [noun] | 169 |
|
| 2 | [Wh det] it [be] difficult [to-vb] | 23 |
|
| 3 | [Wh det] it [be] [to-vb] [noun] | 9 |
|
