| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [be] not [adv] difficult [to-vb] [prep] | 6 |
|
| 2 | be not [adv] difficult [to-vb] [prep] | 6 |
|
| 3 | [is] not [adv] difficult [to-vb] [prep] | 5 |
|
