| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be difficult [prep] [indef pn] [to-vb] | 10 |
|
| 2 | [be] difficult [prep] [indef pn] [to-vb] | 10 |
|
| 3 | [adv] difficult [prep] [indef pn] [to-vb] | 5 |
|
| 4 | [adv] difficult [prep] [indef pn] [to-vb] | 5 |
|
