| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it difficult [to-vb] [adj] [noun] | 65 |
|
| 2 | [vb past] it difficult [to-vb] [adj] | 29 |
|
| 3 | [vb past] it difficult [to-vb] [noun] | 26 |
|
| 4 | [vb past] it [to-vb] [adj] [noun] | 26 |
|
