| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [not/n't] [vb infin] | 21338 |
|
| 2 | [not/n't] [vb infin] at | 1705 |
|
| 3 | could [vb infin] at | 496 |
|
| 4 | could [not/n't] at | 22 |
|
