| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [modal v] have [vb pp] a | 2745 |
|
| 2 | could have [vb pp] [art] | 817 |
|
| 3 | could [verb] [vb pp] a | 335 |
|
| 4 | could [vb infin] [vb pp] a | 335 |
|
| 5 | could have [vb pp] a | 334 |
|
| 6 | could have [verb] a | 318 |
|
