| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | difficult [to-vb] [conj] it [verb] | 16 |
|
| 2 | difficult [to-vb] [conj] it [vb -s] | 12 |
|
| 3 | difficult [to-vb] [subord] it [verb] | 10 |
|
| 4 | difficult [to-vb] as it [verb] | 5 |
|
| 5 | difficult [to-vb] as it [verb] | 5 |
|
