| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [adv] have [been] | 471 |
|
| 2 | [adv] have [been] a | 222 |
|
| 3 | could have [been] a | 219 |
|
| 4 | could [adv] have a | 45 |
|
