| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [verb] [adv] | 3631 |
|
| 2 | could [vb infin] [adv] | 3625 |
|
| 3 | could have [adv] | 227 |
|
| 4 | [modal v] 've [adv] | 37 |
|
| 5 | could 've [adv] | 11 |
|
