| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb past] [pron] could | 2700 |
|
| 2 | [verb] [Wh det] could | 239 |
|
| 3 | [vb past] [Wh det] [modal v] | 215 |
|
| 4 | [vb past] [Wh det] [vb mod] | 215 |
|
| 5 | [vb past] [Wh det] could | 39 |
|
