| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb mod] [adv] [be] [v-ing] | 3322 |
|
| 2 | [modal v] [adv] [be] [v-ing] | 3322 |
|
| 3 | must [adv] [be] [verb] | 1610 |
|
| 4 | must [adv] [be] [v-ing] | 58 |
|
| 5 | must [adv] [be] [v-ing] | 58 |
|
