| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it must [vb infin] [been] some | 12 |
|
| 2 | it must [verb] been some | 12 |
|
| 3 | it must have [been] some | 12 |
|
| 4 | it must [verb] [been] some | 12 |
|
| 5 | it must have [been] some | 11 |
|
