| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | they could [verb] | 4234 |
|
| 2 | [vb past] they [verb] | 3491 |
|
| 3 | [vb past] they could | 327 |
|
| 4 | [vb past] could [verb] | 53 |
|
