| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [adv] be [vb pp] [prep] | 449 |
|
| 2 | [adv] be [vb pp] [prep] [be] | 223 |
|
| 3 | must be [vb pp] [prep] [be] | 75 |
|
