| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun prp] could [adv] have [verb] | 86 |
|
| 2 | could [adv] have [verb] a | 48 |
|
| 3 | [noun prp] could [adv] [verb] a | 42 |
|
| 4 | [noun prp] could have [verb] a | 22 |
|
