| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it is difficult [verb] | 1529 |
|
| 2 | it is difficult [to-vb] | 1523 |
|
| 3 | it is [adj] to determine | 64 |
|
| 4 | it [be] difficult to determine | 25 |
|
| 5 | it be difficult to determine | 25 |
|
| 6 | it [is] difficult to determine | 23 |
|
| 7 | it is difficult to determine | 21 |
|
| 8 | [pron] is difficult to determine | 21 |
|
| 9 | [pers pn] is difficult to determine | 21 |
|
| 10 | it is difficult determine | 21 |
|
