| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could have [vb pp] a | 273 |
|
| 2 | could have [verb] a | 273 |
|
| 3 | [modal v] have done a | 47 |
|
| 4 | could have done [art] | 18 |
|
| 5 | could have done [art] | 18 |
|
| 6 | could have done a | 10 |
|
| 7 | could [vb infin] done a | 10 |
|
| 8 | could [verb] done a | 10 |
|
| 9 | could have done a | 9 |
|
| 10 | could have do a | 9 |
|
