| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [vb past] [adv] [verb] | 4407 |
|
| 2 | it [vb past] [adv] [vb infin] | 3065 |
|
| 3 | it [vb past] [adv] happen | 152 |
|
| 4 | it [verb] [adv] happen | 137 |
|
| 5 | [pron] [vb past] [adv] happen | 82 |
|
