| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | how [vb past] it [verb] | 159 |
|
| 2 | how [vb past] it [vb infin] | 145 |
|
| 3 | [adv] [vb past] it happen | 59 |
|
| 4 | how [verb] it happen | 41 |
|
| 5 | how [vb past] it happen | 39 |
|
| 6 | how [vb past] [pron] happen | 36 |
|
| 7 | how [vb past] [pers pn] happen | 36 |
|
| 8 | how [vb past] it happen | 34 |
|
