| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [vb infin] [been] [subord] i [verb] | 5 |
|
| 2 | must [vb infin] be [subord] i [verb] | 5 |
|
| 3 | must [vb infin] been [subord] i [verb] | 5 |
|
