| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [adv] [verb] | 32838 |
|
| 2 | could [adv] [vb infin] | 32770 |
|
| 3 | [modal v] [adv] have | 22199 |
|
| 4 | could [adv] have | 3257 |
|
