| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [vb infin] be [v-ing] | 289 |
|
| 2 | [vb infin] be [v-ing] to | 56 |
|
| 3 | must be [v-ing] to | 30 |
|
| 4 | must [vb infin] [v-ing] to | 11 |
|
| 5 | must [vb infin] be to | 9 |
|
