| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must be [vb pp] to be | 70 |
|
| 2 | must be seen to be | 32 |
|
| 3 | must be see to be | 32 |
|
| 4 | must be assumed to be | 8 |
|
| 5 | must be assume to be | 8 |
|
