| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [vb infin] [subord] it is [verb] | 7 |
|
| 2 | must [vb infin] [subord] it is [verb] | 7 |
|
| 3 | must [vb infin] [subord] it is [to-vb] | 5 |
|
| 4 | must [vb infin] if it is [verb] | 5 |
|
