| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [be] [adv] difficult [prep] [pron] | 118 |
|
| 2 | [be] difficult [prep] [pron] [to-vb] | 117 |
|
| 3 | [adv] difficult [prep] [pron] [to-vb] | 107 |
|
| 4 | [be] [adv] [prep] [pron] [to-vb] | 105 |
|
