| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | more difficult [to-vb] | 810 |
|
| 2 | [conj] difficult [to-vb] | 210 |
|
| 3 | [conj] more difficult | 106 |
|
| 4 | [conj] more [to-vb] | 82 |
|
