| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [is] [adj] [prep] us [verb] | 115 |
|
| 2 | [is] difficult [prep] [pron] [verb] | 58 |
|
| 3 | [is] difficult [prep] [pers pn] [verb] | 54 |
|
| 4 | [be] difficult [prep] us [verb] | 24 |
|
| 5 | [is] difficult [prep] we [verb] | 17 |
|
