| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [vb mod] [not/n't] [vb infin] happened | 32 |
|
| 2 | it [vb mod] [not/n't] have happened | 32 |
|
| 3 | it [vb mod] n't [vb infin] happened | 20 |
|
| 4 | it would [not/n't] [vb infin] happened | 15 |
|
| 5 | it [vb mod] not [vb infin] happened | 12 |
|
| 6 | it should [not/n't] [vb infin] happened | 8 |
|
