| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [verb] [verb] | 5616 |
|
| 2 | must [verb] [vb pp] | 4653 |
|
| 3 | [vb mod] [verb] happened | 447 |
|
| 4 | [modal v] [verb] happened | 447 |
|
| 5 | must [verb] happen | 50 |
|
| 6 | must [verb] happened | 50 |
|
