| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [verb] be [det] | 100 |
|
| 2 | [verb] be at [det] | 62 |
|
| 3 | must [verb] be at | 40 |
|
| 4 | must [verb] at [det] | 22 |
|
