| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [vb mod] [not/n't] [vb infin] [adv] | 388 |
|
| 2 | it [vb mod] [not/n't] [verb] [adv] | 388 |
|
| 3 | it [vb mod] [adv] happen [adv] | 81 |
|
| 4 | [pron] [vb mod] [not/n't] happen [adv] | 55 |
|
| 5 | it [vb mod] [not/n't] happen [adv] | 55 |
|
| 6 | it [modal v] [not/n't] happen [adv] | 54 |
|
| 7 | it [vb mod] [not/n't] happen [adv] | 54 |
|
