| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must have been [det] [noun sg] | 34 |
|
| 2 | must have [been] [det] [noun sg] | 34 |
|
| 3 | must have [been] [det] [noun sg] | 34 |
|
| 4 | must have [been] some [noun sg] | 29 |
|
| 5 | must have [been] [det] sort | 6 |
|
