| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [modal v] [vb infin] a central role in | 12 |
|
| 2 | [vb mod] [verb] a central role in | 12 |
|
| 3 | [modal v] play a central role in | 9 |
|
| 4 | [modal v] play a central role in | 9 |
|
