| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pers pn] [is] often difficult [to-vb] | 62 |
|
| 2 | it [is] often difficult [verb] | 62 |
|
| 3 | [pers pn] is often difficult [verb] | 59 |
|
| 4 | [pers pn] [is] often difficult determine | 5 |
|
| 5 | [pers pn] [is] often difficult to determine | 5 |
|
