| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [vb mod] have been some [noun] | 14 |
|
| 2 | it [modal v] have been some [noun] | 14 |
|
| 3 | it must have been some [noun] | 12 |
|
| 4 | it must have been some [noun] | 12 |
|
| 5 | it have been [verb] some [noun] | 5 |
|
