| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] must [vb infin] been for | 8 |
|
| 2 | [pron] must have been for | 8 |
|
| 3 | [pron] must have been for | 8 |
|
| 4 | it must [verb] been for | 6 |
|
| 5 | it must [verb] been for | 6 |
|
| 6 | [pers pn] must [verb] been for | 6 |
|
