| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [adv] have been for | 6 |
|
| 2 | could [adv] [verb] been for | 6 |
|
| 3 | could [adv] have been for | 6 |
|
| 4 | could [adv] [vb infin] been for | 6 |
|
| 5 | could not [verb] been for | 5 |
|
| 6 | could [not/n't] [verb] been for | 5 |
|
