| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb past] they could [adv] [vb infin] | 100 |
|
| 2 | [vb past] [pron] could only [vb infin] | 18 |
|
| 3 | [vb past] they [modal v] only [vb infin] | 9 |
|
| 4 | [verb] they could only [vb infin] | 5 |
|
| 5 | [vb past] they could only [verb] | 5 |
|
