| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adj] [to-vb] [subord] [art] [noun] | 412 |
|
| 2 | difficult [to-vb] [conj] [art] [noun] | 144 |
|
| 3 | difficult [verb] [subord] [art] [noun] | 67 |
|
