| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [Wh det] they could [verb] | 258 |
|
| 2 | [Wh det] they could [vb infin] | 238 |
|
| 3 | [Wh det] they [modal v] have | 153 |
|
| 4 | [Wh det] [pron] could have | 88 |
|
| 5 | [pron] they could have | 25 |
|
| 6 | [Wh det] they could have | 20 |
|
