| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] they could have | 44 |
|
| 2 | [verb] [vb pp] they could | 16 |
|
| 3 | [vb pp] they could have | 8 |
|
| 4 | [verb] [vb pp] could have | 7 |
|
