| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [vb infin] [be] [v-ing] [pron] | 46 |
|
| 2 | must [vb infin] [be] [v-ing] for | 18 |
|
| 3 | [vb infin] [be] [v-ing] [pron] for | 10 |
|
