| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] is sometimes difficult [verb] | 23 |
|
| 2 | [pron] is sometimes difficult [to-vb] | 23 |
|
| 3 | [pers pn] is sometimes difficult [verb] | 22 |
|
| 4 | it is sometimes difficult [verb] | 22 |
|
| 5 | it is sometimes difficult [verb] | 22 |
|
