| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pers pn] could have been on | 6 |
|
| 2 | [pron] could have been on | 6 |
|
| 3 | could have been [verb] on | 31 |
|
| 4 | could have been [vb pp] on | 27 |
|
