| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | they could have [verb] | 289 |
|
| 2 | they could have [vb pp] | 287 |
|
| 3 | [pron] could have come | 40 |
|
| 4 | they [modal v] have come | 38 |
|
| 5 | [pers pn] could have come | 36 |
|
| 6 | they could have come | 10 |
|
| 7 | they could have come | 10 |
|
| 8 | they could have come | 10 |
|
| 9 | they could [verb] come | 10 |
|
| 10 | they could [vb infin] come | 10 |
|
