| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [is] often [adj] [to-vb] [subord] | 6 |
|
| 2 | it [is] often difficult [verb] [subord] | 5 |
|
| 3 | it is often [adj] [verb] [subord] | 5 |
|
