| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must have been [prep] [adj] | 51 |
|
| 2 | [modal v] have been [prep] this | 23 |
|
| 3 | must have be [prep] this | 8 |
|
| 4 | must [verb] been [prep] this | 8 |
|
| 5 | must have [be] [prep] this | 8 |
|
| 6 | must have [been] [prep] this | 8 |
|
