| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | this could [adv] happen | 12 |
|
| 2 | [det] could [adv] happen | 11 |
|
| 3 | [det] could not happen | 8 |
|
| 4 | [det] could [not/n't] happen | 8 |
|
| 5 | that could [adv] happen | 7 |
|
| 6 | [det] could n't happen | 5 |
|
