| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb past] they could [adv] [verb] | 100 |
|
| 2 | [vb past] they could [adv] [vb infin] | 100 |
|
| 3 | [vb past] [pron] could [adv] see | 25 |
|
| 4 | [vb past] they [modal v] [adv] see | 7 |
|
| 5 | [verb] they could [adv] see | 6 |
|
| 6 | [vb past] they could [adv] see | 5 |
|
