| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it must have been [prep] | 83 |
|
| 2 | it [modal v] have been for | 14 |
|
| 3 | [pron] must have been for | 8 |
|
| 4 | it must have [be] for | 6 |
|
| 5 | it must have been for | 6 |
|
| 6 | it must have [been] for | 6 |
|
| 7 | [pers pn] must have been for | 6 |
|
| 8 | it must have be for | 6 |
|
| 9 | it must [verb] been for | 6 |
|
