| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be difficult for us [verb] | 24 |
|
| 2 | be difficult for us [to-vb] | 24 |
|
| 3 | is difficult for us [verb] | 13 |
|
| 4 | be difficult for us [verb] | 6 |
|
