| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it does [verb] | 1988 |
|
| 2 | it does [vb infin] | 1958 |
|
| 3 | it [verb] occur | 27 |
|
| 4 | it do occur | 27 |
|
| 5 | [pron] does occur | 21 |
|
| 6 | it does occur | 16 |
|
| 7 | it [vb -s] occur | 16 |
|
