| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must have been [det] | 93 |
|
| 2 | must have been [det] | 92 |
|
| 3 | must have been some | 43 |
|
| 4 | must have been many | 20 |
|
| 5 | must have been those | 5 |
|
| 6 | must have been several | 5 |
|
