| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb past] [pron] could | 2700 |
|
| 2 | [vb past] what [modal v] | 181 |
|
| 3 | [vb past] what [vb mod] | 181 |
|
| 4 | [verb] what could | 160 |
|
| 5 | [vb past] [Wh det] could | 39 |
|
| 6 | [vb past] what could | 35 |
|
| 7 | [vb past] what could | 35 |
|
