| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [vb infin] [prep] a | 1241 |
|
| 2 | could [vb infin] [prep] a | 1241 |
|
| 3 | [modal v] [vb infin] at a | 308 |
|
| 4 | could [vb infin] at [art] | 114 |
|
| 5 | could [vb infin] at a | 29 |
|
| 6 | could [verb] at a | 29 |
|
