| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | doubts have been [verb] about | 8 |
|
| 2 | doubts have been [vb pp] about | 8 |
|
| 3 | doubts have been [verb] about | 6 |
|
| 4 | doubts have been express about | 5 |
|
| 5 | doubts have been expressed about | 5 |
|
