| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be difficult [verb] [conj] | 509 |
|
| 2 | [be] difficult [verb] [conj] | 509 |
|
| 3 | 's [adj] [verb] [conj] | 419 |
|
| 4 | [is] difficult [verb] [conj] | 242 |
|
