| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [is] difficult [verb] such [noun] | 8 |
|
| 2 | [is] difficult [to-vb] such [noun] | 8 |
|
| 3 | is difficult [verb] such [noun] | 8 |
|
| 4 | [is] difficult [verb] such [noun] | 8 |
|
