| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must be [verb] | 12065 |
|
| 2 | must be [vb pp] | 11027 |
|
| 3 | [modal v] be returned | 297 |
|
| 4 | must be return | 38 |
|
| 5 | must be returned | 37 |
|
| 6 | must [be] returned | 37 |
|
| 7 | must [be] returned | 37 |
|
