| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must have been [adj] | 760 |
|
| 2 | [modal v] have been some | 104 |
|
| 3 | must have been [det] | 93 |
|
| 4 | must have [be] some | 43 |
|
| 5 | must have be some | 43 |
|
| 6 | must have [been] some | 43 |
|
| 7 | must [verb] been some | 43 |
|
| 8 | must have been some | 43 |
|
