| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [is] [adv] [adj] [to-vb] [prep] [noun sg] | 194 |
|
| 2 | [is] [adv] difficult [to-vb] [prep] [noun] | 47 |
|
| 3 | [be] [adv] difficult [to-vb] [prep] [noun sg] | 46 |
|
| 4 | [is] [adv] difficult [verb] [prep] [noun sg] | 27 |
|
