| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could have [been] [verb] for a | 6 |
|
| 2 | could have be [verb] for a | 6 |
|
| 3 | could have been [verb] for a | 6 |
|
| 4 | could have [be] [verb] for a | 6 |
|
| 5 | [pron] could have [verb] for a | 5 |
|
| 6 | [pers pn] could have [verb] for a | 5 |
|
| 7 | could [adv] have [verb] for a | 14 |
|
| 8 | could [not/n't] have [verb] for a | 11 |
|
| 9 | could not have [verb] for a | 11 |
|
| 10 | could not have [verb] for a | 6 |
|
| 11 | could n't have [verb] for a | 5 |
|
