| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [to-vb] [conj] [adv] | 2400 |
|
| 2 | difficult [to-vb] [conj] | 1092 |
|
| 3 | difficult [to-vb] [adv] | 415 |
|
| 4 | difficult [conj] [adv] | 138 |
|
