| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | how did [det] [vb infin] | 46 |
|
| 2 | how [vb past] that [vb infin] | 29 |
|
| 3 | how [vb past] this [vb infin] | 14 |
|
| 4 | how [vb past] [det] happen | 14 |
|
| 5 | how [vb past] [det] come | 9 |
|
