| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | why did [pers pn] [vb infin] back | 18 |
|
| 2 | why [vb past] [pers pn] come back | 14 |
|
| 3 | why [vb past] you [vb infin] back | 10 |
|
