| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must have been [det] [noun] | 49 |
|
| 2 | have been [det] [noun] of | 38 |
|
| 3 | must have [det] [noun] of | 27 |
|
| 4 | must have been [noun] of | 12 |
|
