| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb mod] [not/n't] have been [verb] for | 15 |
|
| 2 | [modal v] [not/n't] have been [verb] for | 15 |
|
| 3 | could [not/n't] have been [verb] for | 6 |
|
| 4 | could [not/n't] have been [verb] for | 6 |
|
