| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] must have been a | 317 |
|
| 2 | [pers pn] must have been a | 201 |
|
| 3 | i [modal v] have been a | 41 |
|
| 4 | i [vb mod] have been a | 41 |
|
| 5 | i must have been [art] | 10 |
|
| 6 | i must have been a | 7 |
|
| 7 | i must have be a | 7 |
|
| 8 | i must have [be] a | 7 |
|
| 9 | i must have been a | 7 |
|
| 10 | i must [vb infin] been a | 7 |
|
| 11 | i must [verb] been a | 7 |
|
| 12 | i must have been a | 7 |
|
| 13 | i must have [been] a | 7 |
|
