| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [adv] have been | 471 |
|
| 2 | [adv] have been [det] | 99 |
|
| 3 | could have been [det] | 63 |
|
| 4 | could [adv] have [det] | 18 |
|
