| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] could [not/n't] [vb infin] | 14304 |
|
| 2 | they [modal v] [not/n't] [vb infin] | 6004 |
|
| 3 | they could [adv] [vb infin] | 1883 |
|
| 4 | they could [not/n't] [verb] | 1283 |
|
