| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must have been [adj] | 750 |
|
| 2 | [noun sg] must have been | 542 |
|
| 3 | [noun sg] must have [adj] | 75 |
|
| 4 | [noun sg] have been [adj] | 15 |
|
