| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] could [not/n't] [vb infin] | 14304 |
|
| 2 | [Wh pn] [modal v] [not/n't] [vb infin] | 1239 |
|
| 3 | [Wh pn] could [adv] [vb infin] | 490 |
|
| 4 | [Wh pn] could [not/n't] [verb] | 338 |
|
