| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is difficult [to-vb] [det] [adj] [noun] | 24 |
|
| 2 | is difficult [to-vb] any [adj] [noun] | 21 |
|
| 3 | is difficult [to-vb] [det] [adj] [noun sg] | 17 |
|
| 4 | is difficult [to-vb] [det] [adj] [noun pl] | 11 |
|
