| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb past] [adv] [pron] could | 206 |
|
| 2 | [vb past] [Wh adv] [pron] could | 85 |
|
| 3 | [verb] why [pron] could | 49 |
|
| 4 | [vb past] why [pron] [modal v] | 30 |
|
| 5 | [vb past] why [pron] [vb mod] | 30 |
|
| 6 | [vb past] why [pron] could | 12 |
|
| 7 | [vb past] why [pron] could | 12 |
|
