| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [not/n't] have been [det] | 19 |
|
| 2 | could n't have been [det] | 12 |
|
| 3 | could not have been [det] | 7 |
|
| 4 | could [not/n't] have been more | 6 |
|
| 5 | could [not/n't] have been that | 6 |
|
