| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | has [verb] an important contribution | 6 |
|
| 2 | has [vb pp] [art] important contribution | 6 |
|
| 3 | has made [art] important contribution | 5 |
|
| 4 | has make [art] important contribution | 5 |
|
