| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb mod] have [been] difficult for | 20 |
|
| 2 | [vb mod] have been difficult for | 20 |
|
| 3 | [vb mod] have [been] difficult for | 20 |
|
| 4 | would have [been] difficult for | 14 |
|
