| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it does [adv] occur | 21 |
|
| 2 | it [vb -s] not occur | 20 |
|
| 3 | it [vb -s] [not/n't] occur | 20 |
|
| 4 | it [vb -s] not occur | 10 |
|
| 5 | it [vb -s] n't occur | 10 |
|
