| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [be] difficult [prep] [pron] [to-vb] | 117 |
|
| 2 | it [be] difficult [prep] [pron] | 102 |
|
| 3 | it [be] [prep] [pron] [to-vb] | 98 |
|
| 4 | it difficult [prep] [pron] [to-vb] | 65 |
|
