| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] difficult [to-vb] | 3607 |
|
| 2 | [adv] [to-vb] [is] | 112 |
|
| 3 | difficult [to-vb] [is] | 40 |
|
| 4 | [adv] difficult [is] | 23 |
|
