| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] difficult [to-vb] | 3607 |
|
| 2 | [adv] difficult [to-vb] | 3329 |
|
| 3 | so [adj] [to-vb] | 1702 |
|
| 4 | so difficult [verb] | 130 |
|
| 5 | so difficult [to-vb] | 128 |
|
