| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | this [vb mod] [verb] prevent | 7 |
|
| 2 | this [vb mod] [vb infin] prevent | 7 |
|
| 3 | this [vb mod] help prevent | 7 |
|
| 4 | this [vb mod] help prevent | 7 |
|
