| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | why do [adv] [verb] | 19 |
|
| 2 | why [vb base] [not/n't] [verb] | 15 |
|
| 3 | why [vb base] n't [verb] | 15 |
|
| 4 | why [vb base] not [verb] | 15 |
|
| 5 | why [vb base] [adv] [vb infin] | 15 |
|
