| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [to-vb] at [adj] [noun] | 1058 |
|
| 2 | difficult [to-vb] [adj] [noun] | 456 |
|
| 3 | difficult [to-vb] at [adj] | 25 |
|
| 4 | difficult [to-vb] at [noun] | 16 |
|
| 5 | difficult at [adj] [noun] | 14 |
|
