| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] difficult [to-vb] [is] | 20 |
|
| 2 | more difficult [to-vb] [be] | 17 |
|
| 3 | more [adj] [to-vb] [is] | 14 |
|
| 4 | more difficult [verb] [is] | 13 |
|
