| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] has been a [adj] factor | 21 |
|
| 2 | [noun sg] have been a [adj] factor | 21 |
|
| 3 | [noun] have been a major factor | 11 |
|
| 4 | [noun pl] have been a [adj] factor | 8 |
|
| 5 | [noun] have been a key factor | 6 |
|
| 6 | [noun] had been a [adj] factor | 5 |
|
