| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it must [vb infin] been | 781 |
|
| 2 | must [vb infin] been [prep] | 294 |
|
| 3 | it must [vb infin] [prep] | 159 |
|
| 4 | it [vb infin] been [prep] | 5 |
|
