| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [vb pp] [adv] at [art] | 224 |
|
| 2 | must be [vb pp] at [art] | 82 |
|
| 3 | must be [vb pp] [adv] [art] | 18 |
|
| 4 | must be [vb pp] [adv] at | 12 |
|
