| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could have [vb pp] [pron] [verb] [pron] | 12 |
|
| 2 | could have [verb] [pers pn] [verb] [pron] | 8 |
|
| 3 | could have [verb] [pron] [to-vb] [pron] | 6 |
|
| 4 | could have [verb] [pron] [verb] [pers pn] | 6 |
|
