| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [coord] it [is] often difficult [verb] | 10 |
|
| 2 | [coord] it be often difficult [verb] | 10 |
|
| 3 | [coord] it [be] often difficult [verb] | 10 |
|
| 4 | [coord] it [be] often difficult [to-vb] | 10 |
|
| 5 | [coord] it is often difficult [verb] | 9 |
|
| 6 | and it [be] often difficult [verb] | 5 |
|
| 7 | but it [be] often difficult [verb] | 5 |
|
