| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [coord] it [be] difficult [verb] | 251 |
|
| 2 | it [be] often difficult [verb] | 72 |
|
| 3 | [coord] it [be] often [verb] | 35 |
|
| 4 | [coord] it [be] often difficult | 12 |
|
