| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | difficult [to-vb] [adj] [noun] of | 70 |
|
| 2 | it difficult [to-vb] [adj] [noun] | 65 |
|
| 3 | it [to-vb] [adj] [noun] of | 18 |
|
| 4 | it difficult [to-vb] [adj] of | 8 |
|
| 5 | it difficult [to-vb] [noun] of | 7 |
|
