| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could have been [verb] [det] | 9 |
|
| 2 | could have [been] [verb] [det] | 9 |
|
| 3 | could have [been] [verb] [det] | 8 |
|
| 4 | could have [been] [vb pp] [det] | 7 |
|
