| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | difficult [to-vb] [conj] is | 8 |
|
| 2 | difficult [to-vb] [conj] [is] | 8 |
|
| 3 | difficult [to-vb] [coord] [is] | 7 |
|
| 4 | difficult [to-vb] and [is] | 6 |
|
| 5 | difficult [to-vb] and [is] | 6 |
|
