| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [verb] been [adj] [prep] | 218 |
|
| 2 | [verb] been [v-ing] [adj] [prep] | 211 |
|
| 3 | must [verb] been [v-ing] [prep] | 81 |
|
| 4 | must [verb] been [v-ing] [adj] | 22 |
|
