| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could not [vb infin] been | 511 |
|
| 2 | could not have been | 510 |
|
| 3 | could not have been | 510 |
|
| 4 | could not [verb] been | 329 |
|
| 5 | could n't [verb] been | 182 |
|
