| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | did [adv] happen | 209 |
|
| 2 | [vb past] not happen | 205 |
|
| 3 | [vb past] [not/n't] happen | 205 |
|
| 4 | [vb past] n't happen | 110 |
|
| 5 | [vb past] not happen | 95 |
|
