| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could have [been] [verb] for | 67 |
|
| 2 | have [been] [verb] for a | 29 |
|
| 3 | could have [been] [verb] a | 12 |
|
| 4 | could have [verb] for a | 8 |
|
