| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have been [vb pp] a [adj] | 436 |
|
| 2 | must have been a [adj] | 202 |
|
| 3 | must have [vb pp] a [adj] | 125 |
|
| 4 | must have been [vb pp] [adj] | 10 |
|
| 5 | must have been [vb pp] a | 6 |
|
