| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | i must have been [prep] | 10 |
|
| 2 | i must [verb] been [prep] | 10 |
|
| 3 | i must [verb] been [prep] | 10 |
|
| 4 | i must have been [prep] | 10 |
|
| 5 | i must [vb infin] been [prep] | 10 |
|
