| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] have played a key role | 10 |
|
| 2 | [pron] have played a key role | 7 |
|
| 3 | [Wh pn] have played a key role | 5 |
|
| 4 | who have played a key role | 5 |
|
| 5 | who have played a key role | 5 |
|
| 6 | have played a key role [prep] | 20 |
|
| 7 | have played a key role [prep] | 20 |
|
| 8 | have played a key role in | 20 |
|
| 9 | have played a key role in | 20 |
|
