| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [adv] have | 3255 |
|
| 2 | could only [verb] | 1356 |
|
| 3 | could only [vb infin] | 1350 |
|
| 4 | [modal v] only have | 477 |
|
| 5 | could only have | 129 |
|
