| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | why not [verb] [adv] | 29 |
|
| 2 | why [not/n't] [vb infin] [adv] | 27 |
|
| 3 | why [not/n't] [verb] so | 6 |
|
| 4 | why [not/n't] do [adv] | 5 |
|
| 5 | why [not/n't] do [adv] | 5 |
|
