| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [vb infin] been [prep] [noun] | 39 |
|
| 2 | must [vb infin] [prep] this [noun] | 22 |
|
| 3 | [vb infin] been [prep] this [noun] | 21 |
|
| 4 | must [vb infin] been [prep] this | 8 |
|
