| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb pp] must be | 174 |
|
| 2 | [be] [vb pp] must | 129 |
|
| 3 | [be] [vb pp] be | 19 |
|
| 4 | [be] must be | 18 |
|
