| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb infin] [to-vb] what happened to | 8 |
|
| 2 | [vb infin] [to-vb] [Wh det] happened to | 8 |
|
| 3 | [vb infin] [to-vb] [pron] happened to | 8 |
|
| 4 | [vb infin] [to-vb] what happened to | 8 |
|
