| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must have [been] [prep] [adj] | 51 |
|
| 2 | [modal v] have [been] [prep] some | 18 |
|
| 3 | must [verb] [been] [prep] some | 6 |
|
| 4 | must have [be] [prep] some | 6 |
|
| 5 | must have [been] [prep] some | 6 |
|
