| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | what [vb past] happen | 1007 |
|
| 2 | what [adv] [vb past] | 635 |
|
| 3 | what [adv] happen | 281 |
|
| 4 | [adv] [vb past] happen | 42 |
|
