| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [not/n't] [verb] | 21358 |
|
| 2 | could [not/n't] [vb infin] | 21338 |
|
| 3 | [not/n't] [verb] [vb infin] | 323 |
|
| 4 | could [verb] [vb infin] | 120 |
|
