| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [verb] [been] [noun prp] | 43 |
|
| 2 | must [vb infin] [been] [noun prp] | 43 |
|
| 3 | must have [been] [noun prp] | 43 |
|
| 4 | must [verb] been [noun prp] | 43 |
|
| 5 | must have [been] [noun prp] | 42 |
|
