| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [modal v] [verb] be [v-ing] [det] | 38 |
|
| 2 | must [verb] be [v-ing] [adj] | 22 |
|
| 3 | must [verb] be [verb] [det] | 18 |
|
| 4 | must [verb] [be] [v-ing] [det] | 12 |
|
