| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] which it [is] [adv] difficult | 7 |
|
| 2 | [prep] which it [is] [adv] difficult | 7 |
|
| 3 | which it [is] [adv] difficult [verb] | 11 |
|
| 4 | which it [is] [adv] difficult [to-vb] | 11 |
|
