| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [vb infin] [conj] [pron] | 861 |
|
| 2 | could [vb infin] [Wh det] [pron] | 177 |
|
| 3 | [vb infin] [conj] [Wh det] [pron] | 142 |
|
| 4 | could [vb infin] [conj] [Wh det] | 21 |
|
