| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb past] [adv] happen | 476 |
|
| 2 | what [adv] happen | 281 |
|
| 3 | [vb past] what happen | 82 |
|
| 4 | [vb past] what [adv] | 43 |
|
