| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it be difficult [to-vb] [noun] | 169 |
|
| 2 | it be difficult [to-vb] this | 27 |
|
| 3 | be difficult [to-vb] this [noun] | 20 |
|
| 4 | it be [to-vb] this [noun] | 12 |
|
