| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [adv] have [verb] | 807 |
|
| 2 | could [adv] [verb] [noun sg] | 378 |
|
| 3 | [adv] have [verb] [noun sg] | 237 |
|
| 4 | could have [verb] [noun sg] | 128 |
|
| 5 | could [adv] have [noun sg] | 13 |
|
