| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [is] [Wh det] happened to [noun] | 8 |
|
| 2 | [is] what [vb past] to [noun] | 8 |
|
| 3 | [is] [Wh det] [vb past] to [noun prp] | 8 |
|
| 4 | 's [Wh det] [vb past] to [noun] | 5 |
|
