| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] [Wh det] [pron] could [vb infin] | 501 |
|
| 2 | [Wh det] [pron] could [not/n't] [vb infin] | 209 |
|
| 3 | [prep] [pron] could [not/n't] [vb infin] | 52 |
|
| 4 | [prep] [Wh det] [pron] could [not/n't] | 49 |
|
