| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [adj] [to-vb] [is] | 139 |
|
| 2 | be difficult [to-vb] [be] | 16 |
|
| 3 | [be] difficult [to-vb] [is] | 13 |
|
| 4 | be difficult [verb] [is] | 13 |
|
