| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must be [vb pp] to be | 70 |
|
| 2 | must be [vb pp] [prep] be | 70 |
|
| 3 | must be seen [prep] be | 32 |
|
| 4 | must be assumed [prep] be | 8 |
|
