| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [verb] been some [noun] of | 10 |
|
| 2 | must [vb infin] been some [noun] of | 10 |
|
| 3 | must have been some [noun] of | 10 |
|
| 4 | must have been some [noun] of | 10 |
|
| 5 | must [verb] been some [noun sg] of | 10 |
|
| 6 | must [verb] been some sort of | 6 |
|
| 7 | must [verb] been some sort of | 6 |
|
