| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [conj] it is sometimes difficult | 9 |
|
| 2 | it is sometimes [adv] difficult | 6 |
|
| 3 | it is sometimes [adv] difficult | 6 |
|
| 4 | it is sometimes difficult [verb] | 22 |
|
| 5 | it is sometimes difficult [to-vb] | 22 |
|
| 6 | it is sometimes difficult [prep] | 6 |
|
| 7 | it is sometimes difficult [prep] | 6 |
|
