| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] difficult [to-vb] [conj] [art] | 66 |
|
| 2 | difficult [to-vb] [conj] of [art] | 16 |
|
| 3 | [adv] difficult [conj] of [art] | 11 |
|
| 4 | [adv] difficult [to-vb] [conj] of | 9 |
|
