| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is [adv] [adj] [to-vb] | 9197 |
|
| 2 | [be] [adv] difficult [to-vb] | 2091 |
|
| 3 | be [adv] difficult [to-vb] | 2091 |
|
| 4 | [is] [adv] difficult [to-vb] | 1218 |
|
| 5 | is [adv] difficult [verb] | 994 |
|
