| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] must be [vb pp] at this | 5 |
|
| 2 | must be [vb pp] at this [noun] | 11 |
|
| 3 | must be [vb pp] at this [noun sg] | 11 |
|
| 4 | must be [vb pp] at this stage | 6 |
|
| 5 | must be [vb pp] at this stage | 6 |
|
