| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could have [vb pp] [prep] a [adj] | 19 |
|
| 2 | could have [verb] [prep] a [adj] | 19 |
|
| 3 | could have [verb] [prep] a [adj] | 19 |
|
| 4 | could have [verb] [prep] a [adj] | 15 |
|
