| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] must be [vb pp] | 2574 |
|
| 2 | must be [vb pp] at | 229 |
|
| 3 | [pron] must be at | 75 |
|
| 4 | [pron] be [vb pp] at | 15 |
|
