| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | why do [pron] [verb] back [prep] | 5 |
|
| 2 | why do [pron] [verb] back [prep] | 5 |
|
| 3 | why do [not/n't] [pron] [verb] back | 27 |
|
| 4 | why do not [pron] [verb] back | 27 |
|
| 5 | why do n't [pron] [verb] back | 27 |
|
| 6 | why do [adv] [pron] [verb] back | 27 |
|
