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