| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have been [vb pp] [prep] some | 469 |
|
| 2 | must have been [vb pp] [prep] | 238 |
|
| 3 | must have [vb pp] [prep] some | 21 |
|
| 4 | must have been [prep] some | 6 |
|
