| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pers pn] could [not/n't] have | 989 |
|
| 2 | [Wh det] [pers pn] could [not/n't] | 255 |
|
| 3 | [Wh det] [pers pn] could have | 83 |
|
| 4 | [Wh det] could [not/n't] have | 22 |
|
