| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb past] it [verb] | 4322 |
|
| 2 | [vb past] it [vb infin] | 1350 |
|
| 3 | [vb past] it occur | 20 |
|
| 4 | [verb] it occur | 16 |
|
| 5 | [vb past] [pron] occur | 13 |
|
