| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be difficult [verb] [prep] [art] | 53 |
|
| 2 | [be] difficult [to-vb] [prep] [art] | 53 |
|
| 3 | [be] difficult [verb] [prep] the | 34 |
|
| 4 | [be] difficult [verb] [prep] a | 17 |
|
| 5 | [be] difficult [verb] in [art] | 15 |
|
| 6 | [be] difficult [verb] with [art] | 6 |
|
| 7 | [be] difficult distinguish [prep] [art] | 6 |
|
| 8 | [be] difficult to distinguish [prep] [art] | 6 |
|
| 9 | [be] difficult [verb] from [art] | 6 |
|
| 10 | [be] difficult [verb] on [art] | 5 |
|
